Catalyst composition and methods for its preparation and use in a polymerization process

ABSTRACT

The present invention relates to a catalyst composition and a method for making the catalyst composition of a polymerization catalyst and a carboxylate metal salt. The invention is also directed to the use of the catalyst composition in the polymerization of olefin(s). In particular, the polymerization catalyst system is supported on a carrier. More particularly, the polymerization catalyst comprises a bulky ligand metallocene-type catalyst system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 09/113,216, filed Jul.10, 1998, now U.S. Pat. No. 7,354,880, issued Apr. 8, 2008, thedisclosure of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a catalyst composition and methods forpreparing the catalyst composition and for its use in a process forpolymerizing olefins. In particular, the invention is directed to amethod for preparing a catalyst composition of a bulky ligandmetallocene-type catalyst system and/or a conventional-type transitionmetal catalyst system, and a carboxylate metal salt.

BACKGROUND OF THE INVENTION

Advances in polymerization and catalysis have resulted in the capabilityto produce many new polymers having improved physical and chemicalproperties useful in a wide variety of superior products andapplications. With the development of new catalysts the choice ofpolymerization-type (solution, slurry, high pressure or gas phase) forproducing a particular polymer has been greatly expanded. Also, advancesin polymerization technology have provided more efficient, highlyproductive and economically enhanced processes. Especially illustrativeof these advances is the development of technology utilizing bulkyligand metallocene-type catalyst systems. Regardless of thesetechnological advances in the polyolefin industry, common problems, aswell as new challenges associated with process operability still exist.For example, the tendency for a gas phase or slurry phase process tofoul and/or sheet remains a challenge.

For example, in a continuous slurry process fouling on the walls of thereactor, which act as a heat transfer surface, can result in manyoperability problems. Poor heat transfer during polymerization canresult in polymer particles adhering to the walls of the reactor. Thesepolymer particles can continue to polymerize on the walls and can resultin a premature reactor shutdown. Also, depending on the reactorconditions, some of the polymer may dissolve in the reactor diluent andredeposit on for example the metal heat exchanger surfaces.

In a typical continuous gas phase process, a recycle system is employedfor many reasons including the removal of heat generated in the processby the polymerization. Fouling, sheeting and/or static generation in acontinuous gas phase process can lead to the ineffective operation ofvarious reactor systems. For example, the cooling mechanism of therecycle system, the temperature probes utilized for process control andthe distributor plate, if affected, can lead to an early reactorshutdown.

Evidence of, and solutions to, various process operability problems havebeen addressed by many in the art. For example, U.S. Pat. Nos.4,792,592, 4,803,251, 4,855,370 and 5,391,657 all discuss techniques forreducing static generation in a polymerization process by introducing tothe process for example, water, alcohols, ketones, and/or inorganicchemical additives; PCT publication WO 97/14721 published Apr. 24, 1997discusses the suppression of fines that can cause sheeting by adding aninert hydrocarbon to the reactor; U.S. Pat. No. 5,627,243 discusses anew type of distributor plate for use in fluidized bed gas phasereactors; PCT publication WO 96/08520 discusses avoiding theintroduction of a scavenger into the reactor; U.S. Pat. No. 5,461,123discusses using sound waves to reduce sheeting; U.S. Pat. No. 5,066,736and EP-A1 0 549 252 discuss the introduction of an activity retarder tothe reactor to reduce agglomerates; U.S. Pat. No. 5,610,244 relates tofeeding make-up monomer directly into the reactor above the bed to avoidfouling and improve polymer quality; U.S. Pat. No. 5,126,414 discussesincluding an oligomer removal system for reducing distributor platefouling and providing for polymers free of gels; EP-A1 0 453 116published Oct. 23, 1991 discusses the introduction of antistatic agentsto the reactor for reducing the amount of sheets and agglomerates; U.S.Pat. No. 4,012,574 discusses adding a surface-active compound, aperfluorocarbon group, to the reactor to reduce fouling; U.S. Pat. No.5,026,795 discusses the addition of an antistatic agent with a liquidcarrier to the polymerization zone in the reactor; U.S. Pat. No.5,410,002 discusses using a conventional Ziegler-Nattatitanium/magnesium supported catalyst system where a selection ofantistatic agents are added directly to the reactor to reduce fouling;U.S. Pat. Nos. 5,034,480 and 5,034,481 discuss a reaction product of aconventional Ziegler-Natta titanium catalyst with an antistat to produceultrahigh molecular weight ethylene polymers; U.S. Pat. No. 3,082,198discusses introducing an amount of a carboxylic acid dependent on thequantity of water in a process for polymerizing ethylene using atitanium/aluminum organometallic catalysts in a hydrocarbon liquidmedium; and U.S. Pat. No. 3,919,185 describes a slurry process using anonpolar hydrocarbon diluent using a conventional Ziegler-Natta-type orPhillips-type catalyst and a polyvalent metal salt of an organic acidhaving a molecular weight of at least 300.

There are various other known methods for improving operabilityincluding coating the polymerization equipment, for example, treatingthe walls of a reactor using chromium compounds as described in U.S.Pat. Nos. 4,532,311 and 4,876,320; injecting various agents into theprocess, for example PCT Publication WO 97/46599 published Dec. 11, 1997discusses feeding into a lean zone in a polymerization reactor anunsupported, soluble metallocene-type catalyst system and injectingantifoulants or antistatic agents into the reactor; controlling thepolymerization rate, particularly on start-up; and reconfiguring thereactor design.

Others in the art to improve process operability have discussedmodifying the catalyst system by preparing the catalyst system indifferent ways. For example, methods in the art include combining thecatalyst system components in a particular order; manipulating the ratioof the various catalyst system components; varying the contact timeand/or temperature when combining the components of a catalyst system;or simply adding various compounds to the catalyst system. Thesetechniques or combinations thereof are discussed in the literature.Especially illustrative in the art is the preparation procedures andmethods for producing bulky ligand metallocene-type catalyst systems,more particularly supported bulky ligand metallocene-type catalystsystems with reduced tendencies for fouling and better operability.Examples of these include: WO 96/11961 published Apr. 26, 1996 discussesas a component of a supported catalyst system an antistatic agent forreducing fouling and sheeting in a gas, slurry or liquid poolpolymerization process; U.S. Pat. No. 5,283,218 is directed towards theprepolymerization of a metallocene catalyst; U.S. Pat. Nos. 5,332,706and 5,473,028 have resorted to a particular technique for forming acatalyst by incipient impregnation; U.S. Pat. Nos. 5,427,991 and5,643,847 describe the chemical bonding of non-coordinating anionicactivators to supports; U.S. Pat. No. 5,492,975 discusses polymer boundmetallocene-type catalyst systems; U.S. Pat. No. 5,661,095 discussessupporting a metallocene-type catalyst on a copolymer of an olefin andan unsaturated silane; PCT publication WO 97/06186 published Feb. 20,1997 teaches removing inorganic and organic impurities after formationof the metallocene-type catalyst itself; PCT publication WO 97/15602published May 1, 1997 discusses readily supportable metal complexes; PCTpublication WO 97/27224 published Jul. 31, 1997 relates to forming asupported transition metal compound in the presence of an unsaturatedorganic compound having at least one terminal double bond; and EP-A2-811638 discusses using a metallocene catalyst and an activating cocatalystin a polymerization process in the presence of a nitrogen containingantistatic agent.

While all these possible solutions might reduce the level of fouling orsheeting somewhat, some are expensive to employ and/or may not reducefouling and sheeting to a level sufficient to successfully operate acontinuous process, particularly a commercial or large-scale process.

Thus, it would be advantageous to have a polymerization process capableof operating continuously with enhanced reactor operability and at thesame time produce new and improved polymers. It would also be highlybeneficial to have a continuously operating polymerization processhaving more stable catalyst productivities, reduced fouling/sheetingtendencies and increased duration of operation.

SUMMARY OF THE INVENTION

This invention provides a method of making a new and improved catalystcomposition and for its use in a polymerizing process. The methodcomprises the step of combining, contacting, blending and/or mixing acatalyst system, preferably a supported catalyst system, with acarboxylate metal salt. In one embodiment the catalyst system comprisesa conventional-type transition metal catalyst compound. In the mostpreferred embodiment the catalyst system comprises a bulky ligandmetallocene-type catalyst compound. The combination of the catalystsystem and the carboxylate metal salt is useful in any olefinpolymerization process. The preferred polymerization processes are a gasphase or a slurry phase process, most preferably a gas phase process.

In an embodiment, the invention provides for a method of making acatalyst composition useful for the polymerization of olefin(s), themethod including combining, contacting, blending and/or mixing apolymerization catalyst with at least one carboxylate metal salt. In anembodiment, the polymerization catalyst is a conventional-typetransition metal polymerization catalyst, more preferably a supportedconventional-type transition metal polymerization catalyst. In the mostpreferred embodiment, the polymerization catalyst is a bulky ligandmetallocene-type catalyst, most preferably a supported bulky ligandmetallocene-type polymerization catalyst.

In one preferred embodiment, the invention is directed to a catalystcomposition comprising a catalyst compound, preferably aconventional-type transition metal catalyst compound, more preferably abulky ligand metallocene-type catalyst compound, an activator and/orcocatalyst, a carrier, and a carboxylate metal salt.

In the most preferred method of the invention, the carboxylate metalsalt is blended, preferably dry blended, and most preferably tumble dryblended or fluidized, with a supported catalyst system or polymerizationcatalyst comprising a carrier. In this most preferred embodiment, thepolymerization catalyst includes at least one bulky ligandmetallocene-type catalyst compound, an activator and a carrier.

In yet another embodiment, the invention relates to a process forpolymerizing olefin(s) in the presence of a catalyst compositioncomprising a polymerization catalyst and a carboxylate metal salt,preferably the polymerization catalyst comprises a carrier, morepreferably the polymerization catalyst comprises one or more ofcombination of a conventional-type catalyst compound and/or a bulkyligand metallocene-type catalyst compound.

In a preferred method for making the catalyst composition of theinvention, the method comprises the steps of combining a bulky ligandmetallocene-type catalyst compound, an activator and a carrier to form asupported bulky ligand metallocene-type catalyst system, and contactingthe supported bulky ligand metallocene-type catalyst compound with acarboxylate metal salt. In the most preferred embodiment, the supportedbulky ligand metallocene-type catalyst system and the carboxylate metalsalt are in a substantially dry state or dried state.

In an embodiment, the invention provides for a process for polymerizingolefin(s) in the presence of a polymerization catalyst having beencombined, contacted, blended, or mixed with at least one carboxylatemetal salt.

DETAILED DESCRIPTION OF THE INVENTION Introduction

The invention is directed toward a method for making a catalystcomposition and to the catalyst composition itself. The invention alsorelates to a polymerization process having improved operability andproduct capabilities using the catalyst composition. It has beensuprisingly discovered that using a carboxylate metal salt incombination with a catalyst system results in a substantially improvedpolymerization process. Particularly surprising is where the catalystsystem is supported on carrier, more so where the catalyst systemincludes a bulky ligand metallocene-type catalyst system, and even moreso where the bulky ligand metallocene-type catalysts are very activeand/or are highly incorporating of comonomer.

While not wishing to be bound by any theory, it is believed that thesebulky ligand metallocene-type catalysts are more prone to sheetingand/or fouling. It is believed that the very high activity catalysts canresult in the generation of extreme heat local to the growing polymerparticle. It is theorized that these extreme conditions lead toincreased levels of sheeting and/or fouling. Also hypothesized is thatthe polymers produced by bulky ligand metallocene-type catalysts formvery tough polymer sheets. Thus, it is difficult to break-up and removeany of these sheets that may form in the reactor.

Furthermore, it was very unexpected that fractional melt index andhigher density polymers could be produced in a polymerization processusing the polymerization catalyst and carboxylate metal salt combinationwith improved operability. This discovery was especially important inthat it is well known in the polymer industry that, from a processoperability standpoint, these types of polymers are difficult toproduce.

Utilizing the polymerization catalysts described below in combinationwith a carboxylate metal salt results in a substantial improvement inprocess operability, a significant reduction in sheeting and fouling,improved catalyst performance, better polymer particle morphology withno adverse effect on the physical polymer properties, and the capabilityto produce a broader range of polymers.

Catalyst Components and Catalyst Systems

All polymerization catalysts including conventional-type transitionmetal catalysts are suitable for use in the polymerizing process of theinvention. However, processes using bulky ligand and/or bridged bulkyligand, metallocene-type catalysts are particularly preferred. Thefollowing is a non-limiting discussion of the various polymerizationcatalysts useful in the invention.

Conventional-Type Transition Metal Catalysts

Conventional-type transition metal catalysts are those traditionalZiegler-Natta catalysts and Phillips-type chromium catalyst well knownin the art. Examples of conventional-type transition metal catalysts arediscussed in U.S. Pat. Nos. 4,115,639, 4,077,904 4,482,687, 4,564,605,4,721,763, 4,879,359 and 4,960,741 all of which are herein fullyincorporated by reference. The conventional-type transition metalcatalyst compounds that may be used in the present invention includetransition metal compounds from Groups III to VIII, preferably IVB toVIB of the Periodic Table of Elements.

These conventional-type transition metal catalysts may be represented bythe formula: MR_(x), where M is a metal from Groups IIIB to VIII,preferably Group IVB, more preferably titanium; R is a halogen or ahydrocarbyloxy group; and x is the valence of the metal M. Non-limitingexamples of R include alkoxy, phenoxy, bromide, chloride and fluoride.Non-limiting examples of conventional-type transition metal catalystswhere M is titanium include TiCl₄, TiBr₄, Ti(OC₂H₅)₃Cl, Ti(OC₂H₅)Cl₃,Ti(OC₄H₉)₃Cl, Ti(OC₃H₇)₂Cl₂, Ti(OC₂H₅)₂Br₂, TiCl₃.1/3AlCl₃ andTi(OC₁₂H₂₅)Cl₃.

Conventional-type transition metal catalyst compounds based onmagnesium/titanium electron-donor complexes that are useful in theinvention are described in, for example, U.S. Pat. Nos. 4,302,565 and4,302,566, which are herein fully incorporate by reference. The MgTiCl₆(ethyl acetate)₄ derivative is particularly preferred. British PatentApplication 2,105,355, herein incorporated by reference, describesvarious conventional-type vanadium catalyst compounds. Non-limitingexamples of conventional-type vanadium catalyst compounds includevanadyl trihalide, alkoxy halides and alkoxides such as VOCl₃,VOCl₂(OBu) where Bu=butyl and VO(OC₂H₅)₃; vanadium tetra-halide andvanadium alkoxy halides such as VCl₄ and VCl₃(OBu); vanadium and vanadylacetyl acetonates and chloroacetyl acetonates such as V(AcAc)₃ andVOCl₂(AcAc) where (AcAc) is an acetyl acetonate. The preferredconventional-type vanadium catalyst compounds are VOCl₃, VCl₄ andVOCl₂—OR where R is a hydrocarbon radical, preferably a C₁ to C₁₀aliphatic or aromatic hydrocarbon radical such as ethyl, phenyl,isopropyl, butyl, propyl, n-butyl, iso-butyl, tertiary-butyl, hexyl,cyclohexyl, naphthyl, etc., and vanadium acetyl acetonates.

Conventional-type chromium catalyst compounds, often referred to asPhillips-type catalysts, suitable for use in the present inventioninclude CrO₃, chromocene, silyl chromate, chromyl chloride (CrO₂Cl₂),chromium-2-ethyl-hexanoate, chromium acetylacetonate (Cr(AcAc)₃), andthe like. Non-limiting examples are disclosed in U.S. Pat. Nos.3,242,099 and 3,231,550, which are herein fully incorporated byreference.

Still other conventional-type transition metal catalyst compounds andcatalyst systems suitable for use in the present invention are disclosedin U.S. Pat. Nos. 4,124,532, 4,302,565, 4,302,566 and 5,763,723 andpublished EP-A2 0 416 815 A2 and EP-A1 0 420 436, which are all hereinincorporated by reference. The conventional-type transition metalcatalysts of the invention may also have the general formulaM′_(t)M″X_(2t)Y_(u)E, where M′ is Mg, Mn and/or Ca; t is a number from0.5 to 2; M″ is a transition metal Ti, V and/or Zr; X is a halogen,preferably Cl, Br or I; Y may be the same or different and is halogen,alone or in combination with oxygen, —NR₂, —OR, —SR, —COOR, or —OSOOR,where R is a hydrocarbyl radical, in particular an alkyl, aryl,cycloalkyl or arylalkyl radical, acetylacetonate anion in an amount thatsatisfies the valence state of M′; u is a number from 0.5 to 20; E is anelectron donor compound selected from the following classes ofcompounds: (a) esters of organic carboxylic acids; (b) alcohols; (c)ethers; (d) amines; (e) esters of carbonic acid; (f) nitriles; (g)phosphoramides, (h) esters of phosphoric and phosphorus acid, and (j)phosphorus oxy-chloride. Non-limiting examples of complexes satisfyingthe above formula include: MgTiCl₅.2CH₃COOC₂H₅, Mg₃Ti₂Cl₁₂.7CH₃COOC₂H₅,MgTiCl₅.6C₂H₅OH, MgTiCl₅.100CH₃OH, MgTiCl₅.tetrahydrofuran, MgTi₂Cl₂.7C₆H₅CN, Mg₃Ti₂C₁₂.6C₆H₅COOC₂H₅, MgTiCl₆.2CH₃COOC₂H₅,MgTiCl₆.6C₅H₅N, MgTiCl₅(OCH₃).2CH₃COOC₂H₅, MgTiCl₅N(C₆H₅)₂.3CH₃ COOC₂H₅,MgTiBr₂Cl₄.2(C₂H₅)₂O, MnTiCl₅.4C₂H₅OH, Mg₃V₂Cl₁₂.7CH₃ COOC₂H₅, MgZrCl₆.4tetrahydrofuran. Other catalysts may include cationic catalysts such asAlCl₃, and other cobalt and iron catalysts well known in the art.

Typically, these conventional-type transition metal catalyst compoundsexcluding some convention-type chromium catalyst compounds are activatedwith one or more of the conventional-type cocatalysts described below.

Conventional-Type Cocatalysts

Conventional-type cocatalyst compounds for the above conventional-typetransition metal catalyst compounds may be represented by the formulaM³M⁴ _(v)X² _(c)R³ _(b−c), wherein M³ is a metal from Group IA, IIA, IIBand IIIA of the Periodic Table of Elements; M⁴ is a metal of Group IA ofthe Periodic Table of Elements; v is a number from 0 to 1; each X² isany halogen; c is a number from 0 to 3; each R³ is a monovalenthydrocarbon radical or hydrogen; b is a number from 1 to 4; and whereinb minus c is at least 1. Other conventional-type organometalliccocatalyst compounds for the above conventional-type transition metalcatalysts have the formula M³R³ _(k), where M³ is a Group IA, IIA, IIBor IIIA metal, such as lithium, sodium, beryllium, barium, boron,aluminum, zinc, cadmium, and gallium; k equals 1, 2 or 3 depending uponthe valency of M³ which valency in turn normally depends upon theparticular Group to which M³ belongs; and each R³ may be any monovalenthydrocarbon radical.

Non-limiting examples of conventional-type organometallic cocatalystcompounds of Group IA, IIA and IIIA useful with the conventional-typecatalyst compounds described above include methyllithium, butyllithium,dihexylmercury, butylmagnesium, diethylcadmium, benzylpotassium,diethylzinc, tri-n-butylaluminum, diisobutyl ethylboron, diethylcadmium,di-n-butylzinc and tri-n-amylboron, and, in particular, the aluminumalkyls, such as tri-hexyl-aluminum, triethylaluminum, trimethylaluminum,and tri-isobutylaluminum. Other conventional-type cocatalyst compoundsinclude mono-organohalides and hydrides of Group IIA metals, and mono-or di-organohalides and hydrides of Group IIIA metals. Non-limitingexamples of such conventional-type cocatalyst compounds includedi-isobutylaluminum bromide, isobutylboron dichloride, methyl magnesiumchloride, ethylberyllium chloride, ethylcalcium bromide,di-isobutylaluminum hydride, methylcadmium hydride, diethylboronhydride, hexylberyllium hydride, dipropylboron hydride, octylmagnesiumhydride, butylzinc hydride, dichloroboron hydride, di-bromo-aluminumhydride and bromocadmium hydride. Conventional-type organometalliccocatalyst compounds are known to those in the art and a more completediscussion of these compounds may be found in U.S. Pat. Nos. 3,221,002and 5,093,415, which are herein fully incorporated by reference.

For purposes of this patent specification and appended claimsconventional-type transition metal catalyst compounds exclude thosebulky ligand metallocene-type catalyst compounds discussed below. Forpurposes of this patent specification and the appended claims the term“cocatalyst” refers to conventional-type cocatalysts orconventional-type organometallic cocatalyst compounds. Bulky ligandmetallocene-type catalyst compounds and catalyst systems for use incombination with a carboxylate metal salt of the invention are describedbelow.

Bulky Ligand Metallocene-Type Catalyst Compounds

Generally, bulky ligand metallocene-type catalyst compounds include halfand full sandwich compounds having one or more bulky ligands includingcyclopentadienyl-type structures or other similar functioning structuresuch as pentadiene, cyclooctatetraendiyl and imides. Typical bulkyligand metallocene-type compounds are generally described as containingone or more ligands capable of η-5 bonding to a transition metal atom,usually, cyclopentadienyl derived ligands or moieties, in combinationwith a transition metal selected from Group 3 to 8, preferably 4, 5 or 6or from the lanthanide and actinide series of the Periodic Table ofElements. Exemplary of these bulky ligand metallocene-type catalystcompounds and catalyst systems are described in for example, U.S. Pat.Nos. 4,530,914, 4,871,705, 4,937,299, 5,017,714, 5,055,438, 5,096,867,5,120,867, 5,124,418, 5,198,401, 5,210,352, 5,229,478, 5,264,405,5,278,264, 5,278,119, 5,304,614, 5,324,800, 5,347,025, 5,350,723,5,384,299, 5,391,790, 5,391,789, 5,399,636, 5,408,017, 5,491,207,5,455,366, 5,534,473, 5,539,124, 5,554,775, 5,621,126, 5,684,098,5,693,730, 5,698,634, 5,710,297, 5,712,354, 5,714,427, 5,714,555,5,728,641, 5,728,839, 5,753,577, 5,767,209, 5,770,753 and 5,770,664 allof which are herein fully incorporated by reference. Also, thedisclosures of European publications EP-A-0 591 756, EP-A-0 520 732,EP-A-0 420 436, EP-B1 0 485 822, EP-B1 0 485 823, EP-A2-0 743 324 andEP-B1 0 518 092 and PCT publications WO 91/04257, WO 92/00333, WO93/08221, WO 93/08199, WO 94/01471, WO 96/20233, WO 97/15582, WO97/19959, WO 97/46567, WO 98/01455, WO 98/06759 and WO 98/011144 are allherein fully incorporated by reference for purposes of describingtypical bulky ligand metallocene-type catalyst compounds and catalystsystems.

In one embodiment, bulky ligand metallocene-type catalyst compounds ofthe invention are represented by the formula:

L^(A)L^(B)MQ  (I)

where M is a metal from the Periodic Table of the Elements and may be aGroup 3 to 10 metal, preferably, a Group 4, 5 or 6 transition metal or ametal from the lanthanide or actinide series, more preferably M is atransition metal from Group 4, even more preferably zirconium, hafniumor titanium. L^(A) and L^(B) are bulky ligands that includecyclopentadienyl derived ligands or substituted cyclopentadienyl derivedligands or heteroatom substituted or heteroatom containingcyclopentadienyl derived ligands, or hydrocarbyl substitutedcyclopentadienyl derived ligands, or moieties such as indenyl ligands,benzindenyl ligands, fluorenyl ligands, octahydrofluorenyl ligands,cyclooctatetraendiyl ligands, azenyl ligands and borabenzene ligands,and the like, including hydrogenated versions thereof. Also, L^(A) andL^(B) may be any other ligand structure capable of π-5 bonding to M, forexample L^(A) and L^(B) may comprises one or more heteroatoms, forexample, nitrogen, silicon, boron, germanium, and phosphorous, incombination with carbon atoms to form a cyclic structure, for example aheterocyclopentadienyl ancillary ligand. Further, each of L^(A) andL^(B) may also be other types of bulky ligands including but not limitedto bulky amides, phosphides, alkoxides, aryloxides, imides, carbolides,borollides, porphyrins, phthalocyanines, corrins and otherpolyazomacrocycles. Each L^(A) and L^(B) may be the same or differenttype of bulky ligand that is π-bonded to M.

Each L^(A) and L^(B) may be substituted with a combination ofsubstituent groups R. Non-limiting examples of substituent groups Rinclude hydrogen or linear, branched, alkyl radicals or cyclic alkyl,alkenyl, alkynl or aryl radicals or combination thereof having from 1 to30 carbon atoms or other substituents having up to 50 non-hydrogen atomsthat can also be substituted. Non-limiting examples of alkylsubstituents R include methyl, ethyl, propyl, butyl, pentyl, hexyl,cyclopentyl, cyclohexyl, benzyl or phenyl groups, halogens and the like,including all their isomers, for example tertiary butyl, iso-propyl,etc. Other hydrocarbyl radicals include fluoromethyl, fluoroethyl,difluoroethyl, iodopropyl, bromohexyl, chlorobenzyl and hydrocarbylsubstituted organometalloid radicals including trimethylsilyl,trimethylgermyl, methyldiethylsilyl and the like; andhalocarbyl-substituted organometalloid radicals includingtris(trifluoromethyl)-silyl, methyl-bis(difluoromethyl)silyl,bromomethyldimethylgermyl and the like; and disubstitiuted boronradicals including dimethylboron for example; and disubstitutedpnictogen radicals including dimethylamine, dimethylphosphine,diphenylamine, methylphenylphosphine, chalcogen radicals includingmethoxy, ethoxy, propoxy, phenoxy, methylsulfide and ethylsulfide.Non-hydrogen substituents R include the atoms carbon, silicon, nitrogen,phosphorous, oxygen, tin, germanium and the like including olefins suchas but not limited to olefinically unsaturated substituents includingvinyl-terminated ligands, for example but-3-enyl, 2-vinyl, or hexene-1.Also, at least two R groups, preferably two adjacent R groups are joinedto form a ring structure having from 4 to 30 atoms selected from carbon,nitrogen, oxygen, phosphorous, silicon, germanium, boron or acombination thereof. Also, an R group such as 1-butanyl may form acarbon sigma bond to the metal M.

Other ligands may be bonded to the transition metal, such as a leavinggroup Q. Q may be independently monoanionic labile ligands having asigma-bond to M. Non-limiting examples of Q include weak bases such asamines, phosphines, ether, carboxylates, dienes, hydrocarbyl radicalshaving from 1 to 20 carbon atoms, hydrides or halogens and the like, andcombinations thereof. Other examples of Q radicals include thosesubstituents for R as described above and including cyclohexyl, heptyl,tolyl, trifluoromethyl, tetramethylene and pentamethylene, methylidene,methyoxy, ethyoxy, propoxy, phenoxy, bis(N-methylanilide),dimethylamide, dimethylphosphide radicals and the like.

In addition, bulky ligand metallocene-type catalyst compounds of theinvention are those where L^(A) and L^(B) are bridged to each other by abridging group, A. These bridged compounds are known as bridged, bulkyligand metallocene-type catalyst compounds. Non-limiting examples ofbridging group A include bridging radicals of at least one Group 14atom, such as but not limited to carbon, oxygen, nitrogen, silicon,germanium and tin, preferably carbon, silicon and germanium, mostpreferably silicon. Other non-limiting examples of bridging groups Ainclude dimethylsilyl, diethylsilyl, methylethylsilyl,trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di-n-butylsilyl,silylcyclobutyl, di-1-propylsilyl, di-cyclohexylsilyl, di-phenylsilyl,cyclohexylphenylsilyl, t-butylcyclohexylsilyl, di-t-butylphenylsilyl,di(p-tolyl)silyl, dimethylgermyl, diethylgermyl, methylene,dimethylmethylene, diphenylmethylene, ethylene, 1-2-dimethylethylene,1,2-diphenylethylene, 1,1,2,2-tetramethylethylene,dimethylmethylenedimethylsilyl, methylenediphenylgermyl, methylamine,phenylamine, cyclohexylamine, methylphosphine, phenylphosphine,cyclohexylphosphine and the like.

In another embodiment, the bulky ligand metallocene-type catalystcompound of the invention is represented by the formula:

(C₅H_(4-d)R_(d))A_(x)(C₅H_(4-d)R_(d))M Qg⁻²  (II)

wherein M is a Group 4, 5, 6 transition metal, (C₅H_(4-d)R_(d)) is anunsubstituted or substituted cyclopentadienyl derived bulky ligandbonded to M, each R, which can be the same or different, is hydrogen ora substituent group containing up to 50 non-hydrogen atoms orsubstituted or unsubstituted hydrocarbyl having from 1 to 30 carbonatoms or combinations thereof, or two or more carbon atoms are joinedtogether to form a part of a substituted or unsubstituted ring or ringsystem having 4 to 30 carbon atoms, A is one or more of, or acombination of carbon, germanium, silicon, tin, phosphorous or nitrogenatom containing radical bridging two (C₅H_(4-d)R_(d)) rings; moreparticularly, non-limiting examples of A may be represented by R′₂C,R′₂Si, R′₂Si R′₂Si, R′₂Si R′₂C, R′₂Ge, R′₂Ge, R′₂Si R′₂Ge, R′₂GeR′₂C,R′N, R′P, R′₂C R′N, R′₂C R′P, R′₂Si R′N, R′₂Si R′P, R′₂GeR′N, R′₂Ge R′P,where R′ is independently, a radical group which is hydride, C₁₋₃₀hydrocarbyl, substituted hydrocarbyl, halocarbyl, substitutedhalocarbyl, hydrocarbyl-substituted organometalloid,halocarbyl-substituted organometalloid, disubstituted boron,disubstituted pnictogen, substituted chalcogen, or halogen; each Q whichcan be the same or different is a hydride, substituted or unsubstituted,linear, cyclic or branched, hydrocarbyl having from 1 to 30 carbonatoms, halogen, alkoxides, aryloxides, amides, phosphides, or any otherunivalent anionic ligand or combination thereof; also, two Q's togethermay form an alkylidene ligand or cyclometallated hydrocarbyl ligand orother divalent anionic chelating ligand, where g is an integercorresponding to the formal oxidation state of M, and d is an integerselected from the 0, 1, 2, 3 or 4 and denoting the degree ofsubstitution and x is an integer from 0 to 1.

In one embodiment, the bulky ligand metallocene-type catalyst compoundsare those where the R substituents on the bulky ligands L^(A), L^(B),(C₅H_(4-d)R_(d)) of formulas (I) and (II) are substituted with the sameor different number of substituents on each of the bulky ligands.

In a preferred embodiment, the bulky ligand metallocene-type catalyst isrepresented by formula (II), where x is 1.

Other bulky ligand metallocene-type catalysts compounds useful in theinvention include bridged, mono-bulky ligand heteroatom containingmetallocene-type compounds. These types of catalysts and catalystsystems are described in, for example, PCT publication WO 92/00333, WO94/07928, WO 91/04257, WO 94/03506, WO96/00244 and WO 97/15602 and U.S.Pat. Nos. 5,057,475, 5,096,867, 5,055,438, 5,198,401, 5,227,440 and5,264,405 and European publication EP-A-0 420 436, all of which areherein fully incorporated by reference. Other bulky ligandmetallocene-type catalysts useful in the invention may include thosedescribed in U.S. Pat. Nos. 5,064,802, 5,145,819, 5,149,819, 5,243,001,5,239,022, 5,276,208, 5,296,434, 5,321,106, 5,329,031, 5,304,614,5,677,401 and 5,723,398 and PCT publications WO 93/08221, WO 93/08199,WO 95/07140, WO 98/11144 and European publications EP-A-0 578 838,EP-A-0 638 595, EP-B-0 513 380 and EP-A1-0 816 372, all of which areherein fully incorporated by reference.

In another embodiment of this invention the bridged, mono-bulky ligandheteroatom containing metallocene-type catalyst compounds useful in theinvention are represented by the formula:

wherein M is Ti, Zr or Hf; (C₅H_(5-y-x)R_(x)) is a cyclopentadienyl ringor ring system which is substituted with from 0 to 5 substituent groupsR, “x” is 0, 1, 2, 3, 4 or 5 denoting the degree of substitution, andeach substituent group R is, independently, a radical selected from agroup consisting of C₁-C₂₀ hydrocarbyl radicals, substituted C₁-C₂₀hydrocarbyl radicals wherein one or more hydrogen atoms is replaced by ahalogen atom, C₁-C₂₀ hydrocarbyl-substituted metalloid radicals whereinthe metalloid is selected from the Group 14 of the Periodic Table ofElements, and halogen radicals or (C₅H_(5-y-x)R_(x)) is acyclopentadienyl ring in which two adjacent R-groups are joined formingC₄-C₂₀ ring to give a saturated or unsaturated polycycliccyclopentadienyl ligand such as indenyl, tetrahydroindenyl, fluorenyl oroctahydrofluorenyl;

(JR′_(z-1-y)) is a heteroatom ligand in which J is an element with acoordination number of three from Group 15 or an element with acoordination number of two from Group 16 of the Periodic Table ofElements, preferably nitrogen, phosphorus, oxygen or sulfur withnitrogen being preferred, and each R′ is, independently a radicalselected from a group consisting of C₁-C₂₀ hydrocarbyl radicals whereinone or more hydrogen atoms is replaced by a halogen atom, y is 0 or 1,and “z” is the coordination number of the element J;

each Q is, independently any univalent anionic ligand such as halogen,hydride, or substituted or unsubstituted C₁-C₃₀ hydrocarbyl, alkoxide,aryloxide, amide or phosphide, provided that two Q may be an alkylidene,a cyclometallated hydrocarbyl or any other divalent anionic chelatingligand; and n may be 0, 1 or 2;

A is a covalent bridging group containing a Group 15 or 14 element suchas, but not limited to, a dialkyl, alkylaryl or diaryl silicon orgermanium radical, alkyl or aryl phosphine or amine radical, or ahydrocarbyl radical such as methylene, ethylene and the like;

L′ is a Lewis base such as diethylether, tetraethylammonium chloride,tetrahydrofuran, dimethylaniline, aniline, trimethylphosphine,n-butylamine, and the like; and w is a number from 0 to 3. Additionally,L′ may be bonded to any of R, R′ or Q and n is 0, 1, 2 or 3.

In another embodiment, the bulky ligand type metallocene-type catalystcompound is a complex of a transition metal, a substituted orunsubstituted pi-bonded ligand, and one or more heteroallyl moieties,such as those described in U.S. Pat. Nos. 5,527,752 and 5,747,406 andEP-B1-0 735 057, all of which are herein fully incorporated byreference. Preferably, the bulky ligand type metallocene-type catalystcompound, the monocycloalkadienyl catalyst compound, may be representedby one of the following formulas:

wherein M is a transition metal from Group 4, 5 or 6, preferablytitanium zirconium or hafnium, most preferably zirconium or hafnium; Lis a substituted or unsubstituted, pi-bonded ligand coordinated to M,preferably L is a cycloalkadienyl bulky ligand, for examplecyclopentadienyl, indenyl or fluorenyl bulky ligands, optionally withone or more hydrocarbyl substituent groups having from 1 to 20 carbonatoms; each Q is independently selected from the group consisting of—O—, —NR—, —CR₂— and —S—, preferably oxygen; Y is either C or S,preferably carbon; Z is selected from the group consisting of —OR, —NR₂,—CR₃, —SR, —SiR₃, —PR₂, —H, and substituted or unsubstituted arylgroups, with the proviso that when Q is —NR— then Z is selected from thegroup consisting of —OR, —NR₂, —SR, —SiR₃, —PR₂ and —H, preferably Z isselected from the group consisting of —OR, —CR₃ and —NR₂; n is 1 or 2,preferably 1; A is a univalent anionic group when n is 2 or A is adivalent anionic group when n is 1, preferably A is a carbamate,carboxylate, or other heteroallyl moiety described by the Q, Y and Zcombination; and each R is independently a group containing carbon,silicon, nitrogen, oxygen, and/or phosphorus where one or more R groupsmay be attached to the L substituent, preferably R is a hydrocarbongroup containing from 1 to 20 carbon atoms, most preferably an alkyl,cycloalkyl, or an aryl group and one or more may be attached to the Lsubstituent; and T is a bridging group selected from the groupconsisting of alkylene and arylene groups containing from 1 to 10 carbonatoms optionally substituted with carbon or heteroatom(s), germanium,silicon and alkyl phosphine; and m is 2 to 7, preferably 2 to 6, mostpreferably 2 or 3.

In formulas (IV) and (V), the supportive substituent formed by Q, Y andZ is a unicharged polydentate ligand exerting electronic effects due toits high polarizability, similar to the cyclopentadienyl ligand. In themost preferred embodiments of this invention, the disubstitutedcarbamates and the carboxylates are employed. Non-limiting examples ofthese bulky ligand metallocene-type catalyst compounds include indenylzirconium tris(diethylcarbamate), indenyl zirconiumtris(trimethylacetate), indenyl zirconium tris(p-toluate), indenylzirconium tris(benzoate), (1-methylindenyl)zirconiumtris(trimethylacetate), (2-methylindenyl)zirconiumtris(diethylcarbamate), (methylcyclopentadienyl)zirconiumtris(trimethylacetate), cyclopentadienyl tris(trimethylacetate),tetrahydroindenyl zirconium tris(trimethylacetate), and(pentamethyl-cyclopentadienyl)zirconium tris(benzoate). Preferredexamples are indenyl zirconium tris(diethylcarbamate), indenyl zirconiumtris(trimethylacetate), and (methylcyclopentadienyl)zirconiumtris(trimethylacetate).

In another embodiment of the invention the bulky ligand metallocene-typecatalyst compounds are those nitrogen containing heterocyclic ligandcomplexes, also known as transition metal catalysts based on bidentateligands containing pyridine or quinoline moieties, such as thosedescribed in WO 96/33202 and U.S. Pat. No. 5,637,660, which are hereinincorporated by reference.

It is within the scope of this invention, in one embodiment, that bulkyligand metallocene-type catalyst compound complexes of Ni²⁺ and Pd²⁺described in the articles Johnson, et al., “New Pd(II)— and Ni(II)—Based Catalysts for Polymerization of Ethylene and a-Olefins”, J. Am.Chem. Soc. 1995, 117, 6414-6415 and Johnson, et al., “Copolymerizationof Ethylene and Propylene with Functionalized Vinyl Monomers byPalladium(II) Catalysts”, J. Am. Chem. Soc., 1996, 118, 267-268, and WO96/23010 published Aug. 1, 1996, which are all herein fully incorporatedby reference, may be combined with a carboxylate metal salt for use inthe process of invention. These complexes can be either dialkyl etheradducts, or alkylated reaction products of the described dihalidecomplexes that can be activated to a cationic state by theconventional-type cocatalysts or the activators of this inventiondescribed below.

Also included as bulky ligand metallocene-type catalyst compounds arethose diimine based ligands for Group 8 to 10 metal compounds disclosedin PCT publications WO 96/23010 and WO 97/48735 and Gibson, et. al.,Chem. Comm., pp. 849-850 (1998), all of which are herein incorporated byreference.

Other bulky ligand metallocene-type catalyst compounds are those Group 5and 6 metal imido complexes described in EP-A2-0 816 384, which isincorporated herein by reference. In addition, bulky ligandmetallocene-type catalysts include bridged bis(arylamido) Group 4compounds described by D. H. McConville, et. al., in Organometallics1195, 14, 5478-5480, which is herein incorporated by reference.

It is contemplated in some embodiments, that the bulky ligands of themetallocene-type catalyst compounds of the invention described above maybe asymmetrically substituted in terms of additional substituents ortypes of substituents, and/or unbalanced in terms of the number ofadditional substituents on the bulky ligands or the bulky ligandsthemselves are different.

It is also contemplated that in one embodiment, the bulky ligandmetallocene-type catalysts of the invention include their structural oroptical or enantiomeric isomers (meso and racemic isomers) and mixturesthereof. In another embodiment the bulky ligand metallocene-typecompounds of the invention may be chiral and/or a bridged bulky ligandmetallocene-type catalyst compound.

Activator and Activation Methods for the Bulky Ligand Metallocene-TypeCatalyst Compounds

The above described bulky ligand metallocene-type catalyst compounds ofthe invention are typically activated in various ways to yield catalystcompounds having a vacant coordination site that will coordinate,insert, and polymerize olefin(s).

For the purposes of this patent specification and appended claims, theterm “activator” is defined to be any compound or component or methodwhich can activate any of the bulky ligand metallocene-type catalystcompounds of the invention as described above. Non-limiting activators,for example may include a Lewis acid or a non-coordinating ionicactivator or ionizing activator or any other compounds including Lewisbases, aluminum alkyls, conventional-type cocatalysts (previouslydescribed herein) and combinations thereof that can convert a neutralbulky ligand metallocene-type catalyst compound to a catalyticallyactive bulky ligand metallocene-type cation. It is within the scope ofthis invention to use alumoxane and/or modified alumoxane and/oraluminum alkyls as an activator, and/or to also use ionizing activators,neutral or ionic, such as tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)boron or a trisperfluorophenyl boronmetalloid precursor that would ionize the neutral metallocene compound.

In one embodiment, an activation method using ionizing ionic compoundsnot containing an active proton but capable of producing both a bulkyligand metallocene-type catalyst cation and a noncoordinating anion arealso contemplated, and are described in EP-A-0 426 637, EP-A-0 573 403and U.S. Pat. No. 5,387,568, which are all herein incorporated byreference.

There are a variety of methods for preparing alumoxane and modifiedalumoxanes, non-limiting examples of which are described in U.S. Pat.Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734,4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801,5,235,081, 5,157,137, 5,103,031, 5,391,793, 5,391,529, 5,693,838,5,731,253, 5,731,451 5,744,656 and European publications EP-A-0 561 476,EP-B1-0 279 586 and EP-A-0 594-218, and PCT publication WO 94/10180, allof which are herein fully incorporated by reference.

Ionizing compounds may contain an active proton, or some other cationassociated with but not coordinated to or only loosely coordinated tothe remaining ion of the ionizing compound. Such compounds and the likeare described in European publications EP-A-0 570 982, EP-A-0 520 732,EP-A-0 495 375, EP-A-500 944, EP-A-0 277 003 and EP-A-0 277 004, andU.S. Pat. Nos. 5,153,157, 5,198,401, 5,066,741, 5,206,197, 5,241,025,5,384,299 and 5,502,124 and U.S. patent application Ser. No. 08/285,380,filed Aug. 3, 1994, all of which are herein fully incorporated byreference.

Other activators include those described in PCT publication WO 98/07515such as tris(2,2′,2″-nonafluorobiphenyl)fluoroaluminate, whichpublication is fully incorporated herein by reference. Combinations ofactivators are also contemplated by the invention, for example,alumoxanes and ionizing activators in combinations, see for example, PCTpublications WO 94/07928 and WO 95/14044 and U.S. Pat. Nos. 5,153,157and 5,453,410 all of which are herein fully incorporated by reference.WO 98/09996 incorporated herein by reference describes activating bulkyligand metallocene-type catalyst compounds with perchlorates, periodatesand iodates including their hydrates. Also, methods of activation suchas using radiation (see EP-B1-0 615 981 herein incorporated byreference) and the like are also contemplated as activating methods forthe purposes of rendering the neutral bulky ligand metallocene-typecatalyst compound or precursor to a bulky ligand metallocene-type cationcapable of polymerizing olefin(s).

Mixed Catalysts

It is also within the scope of this invention that the above describedbulky ligand metallocene-type catalyst compounds can be combined withone or more of the catalyst compounds represented by formula (I), (II),(III), (IV) and (V) with one or more activators or activation methodsdescribed above.

It is further contemplated by the invention that other catalysts can becombined with the bulky ligand metallocene-type catalyst compounds ofthe invention. For example, see U.S. Pat. Nos. 4,937,299, 4,935,474,5,281,679, 5,359,015, 5,470,811, and 5,719,241 all of which are hereinfully incorporated herein reference.

In another embodiment of the invention one or more bulky ligandmetallocene-type catalyst compounds or catalyst systems may be used incombination with one or more conventional-type catalyst compounds orcatalyst systems. Non-limiting examples of mixed catalysts and catalystsystems are described in U.S. Pat. Nos. 4,159,965, 4,325,837, 4,701,432,5,124,418, 5,077,255, 5,183,867, 5,391,660, 5,395,810, 5,691,264,5,723,399 and 5,767,031 and PCT Publication WO 96/23010 published Aug.1, 1996, all of which are herein fully incorporated by reference.

It is further contemplated that two or more conventional-type transitionmetal catalysts may be combined with one or more conventional-typecocatalysts. Non-limiting examples of mixed conventional-type transitionmetal catalysts are described in for example U.S. Pat. Nos. 4,154,701,4,210,559, 4,263,422, 4,672,096, 4,918,038, 5,198,400, 5,237,025,5,408,015 and 5,420,090, all of which are herein incorporated byreference.

Method for Supporting

The above described bulky ligand metallocene-type catalyst compounds andcatalyst systems and conventional-type transition metal catalystcompounds and catalyst systems may be combined with one or more supportmaterials or carriers using one of the support methods well known in theart or as described below. In the preferred embodiment, the method ofthe invention uses a polymerization catalyst in a supported form. Forexample, in a most preferred embodiment, a bulky ligand metallocene-typecatalyst compound or catalyst system is in a supported form, for exampledeposited on, contacted with, or incorporated within, adsorbed orabsorbed in a support or carrier.

The terms “support” or “carrier” are used interchangeably and are anyporous or non-porous support material, preferably a porous supportmaterial, for example, talc, inorganic oxides and inorganic chlorides.Other carriers include resinous support materials such as polystyrene, afunctionalized or crosslinked organic supports, such as polystyrenedivinyl benzene polyolefins or polymeric compounds, or any other organicor inorganic support material and the like, or mixtures thereof.

The preferred carriers are inorganic oxides that include those Group 2,3, 4, 5, 13 or 14 metal oxides. The preferred supports includes silica,alumina, silica-alumina, magnesium chloride, and mixtures thereof. Otheruseful supports include magnesia, titania, zirconia, montmorillonite andthe like. Also, combinations of these support materials may be used, forexample, silica-chromium and silica-titania.

It is preferred that the carrier, most preferably an inorganic oxide,has a surface area in the range of from about 10 to about 700 m²/g, porevolume in the range of from about 0.1 to about 4.0 cc/g and averageparticle size in the range of from about 10 to about 500 μm. Morepreferably, the surface area of the carrier is in the range of fromabout 50 to about 500 m²/g, pore volume of from about 0.5 to about 3.5cc/g and average particle size of from about 20 to about 200 μm. Mostpreferably the surface area of the carrier is in the range of from about100 to about 400 m²/g, pore volume from about 0.8 to about 3.0 cc/g andaverage particle size is from about 20 to about 100 μm. The average poresize of a carrier of the invention is typically in the range of fromabout 10 Å to 1000 Å, preferably 50 Å to about 500 Å, and mostpreferably 75 Å to about 350 Å.

Examples of supporting the bulky ligand metallocene-type catalystsystems of the invention are described in U.S. Pat. Nos. 4,701,432,4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892,5,240,894, 5,332,706, 5,346,925, 5,422,325, 5,466,649, 5,466,766,5,468,702, 5,529,965, 5,554,704, 5,629,253, 5,639,835, 5,625,015,5,643,847, 5,665,665, 5,698,487, 5,714,424, 5,723,400, 5,723,402,5,731,261, 5,759,940, 5,767,032 and 5,770,664 and U.S. ApplicationSerial Nos. 271,598 filed Jul. 7, 1994 and 788,736 filed Jan. 23, 1997and PCT publications WO 95/32995, WO 95/14044, WO 96/06187 and WO97/02297 all of which are herein fully incorporated by reference.

Examples of supporting the conventional-type catalyst systems of theinvention are described in U.S. Pat. Nos. 4,894,424, 4,376,062,4,395,359, 4,379,759, 4,405,495 4,540,758 and 5,096,869, all of whichare herein incorporated by reference.

It is contemplated that the bulky ligand metallocene-type catalystcompounds of the invention may be deposited on the same or separatesupports together with an activator, or the activator may be used in anunsupported form, or may be deposited on a support different from thesupported bulky ligand metallocene-type catalyst compounds of theinvention, or any combination thereof.

There are various other methods in the art for supporting apolymerization catalyst compound or catalyst system of the invention.For example, the bulky ligand metallocene-type catalyst compound of theinvention may contain a polymer bound ligand as described in U.S. Pat.Nos. 5,473,202 and 5,770,755, which is herein fully incorporated byreference; the bulky ligand metallocene-type catalyst system of theinvention may be spray dried as described in U.S. Pat. No. 5,648,310,which is herein fully incorporated by reference; the support used withthe bulky ligand metallocene-type catalyst system of the invention isfunctionalized as described in European publication EP-A-0 802 203,which is herein fully incorporated by reference; or at least onesubstituent or leaving group is selected as described in U.S. Pat. No.5,688,880, which is herein fully incorporated by reference.

In a preferred embodiment, the invention provides for a supported bulkyligand metallocene-type catalyst system that includes a surface modifierthat is used in the preparation of the supported catalyst system, asdescribed in PCT publication WO 96/11960 which is herein fullyincorporated by reference.

A preferred method for producing the supported bulky ligandmetallocene-type catalyst system of the invention is described below andcan be found in U.S. application Ser. Nos. 265,533, filed Jun. 24, 1994and 265,532, filed Jun. 24, 1994 and PCT publications WO 96/00245 and WO96/00243 both published Jan. 4, 1996, all of which are herein fullyincorporated by reference. In this preferred method, the bulky ligandmetallocene-type catalyst compound is slurried in a liquid to form ametallocene solution and a separate solution is formed containing anactivator and a liquid. The liquid may be any compatible solvent orother liquid capable of forming a solution or the like with the bulkyligand metallocene-type catalyst compounds and/or activator of theinvention. In the most preferred embodiment the liquid is a cyclicaliphatic or aromatic hydrocarbon, most preferably toluene. The bulkyligand metallocene-type catalyst compound and activator solutions aremixed together and added to a porous support or the porous support isadded to the solutions such that the total volume of the bulky ligandmetallocene-type catalyst compound solution and the activator solutionor the bulky ligand metallocene-type catalyst compound and activatorsolution is less than five times the pore volume of the porous support,more preferably less than four times, even more preferably less thanthree times; preferred ranges being from 1.1 times to 3.5 times rangeand most preferably in the 1.2 to 3 times range.

Procedures for measuring the total pore volume of a porous support arewell known in the art. Details of one of these procedures is discussedin Volume 1, Experimental Methods in Catalytic Research (Academic Press,1968) (specifically see pages 67-96). This preferred procedure involvesthe use of a classical BET apparatus for nitrogen absorption. Anothermethod well known in the art is described in Innes, Total Porosity andParticle Density of Fluid Catalysts By Liquid Titration, Vol. 28, No. 3,Analytical Chemistry 332-334 (March, 1956).

The mole ratio of the metal of the activator component to the metal ofthe bulky ligand metallocene-type catalyst compounds are in the range ofbetween 0.3:1 to 2000:1, preferably 20:1 to 800:1, and most preferably50:1 to 500:1. Where the activator is an ionizing activator such asthose based on the anion tetrakis(pentafluorophenyl)boron, the moleratio of the metal of the activator component to the metal component ofthe catalyst is preferably in the range of between 0.3:1 to 3:1.

In one embodiment of the invention, olefin(s), preferably C₂ to C₃₀olefin(s) or alpha-olefin(s), preferably ethylene or propylene orcombinations thereof are prepolymerized in the presence of the bulkyligand metallocene-type catalyst system and/or a conventional-typetransition metal catalysts of the invention prior to the mainpolymerization. The prepolymerization can be carried out batchwise orcontinuously in gas, solution or slurry phase including at elevatedpressures. The prepolymerization can take place with any olefin monomeror combination and/or in the presence of any molecular weightcontrolling agent such as hydrogen. For examples of prepolymerizationprocedures, see U.S. Pat. Nos. 4,748,221, 4,789,359, 4,923,833,4,921,825, 5,283,278 and 5,705,578 and European publication EP-B-0279863 and PCT Publication WO 97/44371 all of which are herein fullyincorporated by reference. A prepolymerized catalyst system for purposesof this patent specification and appended claim is a supported catalystsystem.

Carboxylate Metal Salt

Carboxylate metal salts are well known in the art as additives for usewith polyolefins, for example as a film processing aid. These types ofpost reactor processing additives are commonly used as emulsifyingagents, antistat and antifogging agents, stabilizers, foaming aids,lubrication aids, mold release agents, nucleating agents, and slip andantiblock agents and the like. Thus, it was truly unexpected that thesepost reactor agents or aids would be useful with a polymerizationcatalyst to improve the operability of a polymerization process.

For the purposes of this patent specification and appended claims theterm “carboxylate metal salt” is any mono- or di- or tri-carboxylic acidsalt with a metal portion from the Periodic Table of Elements.Non-limiting examples include saturated, unsaturated, aliphatic,aromatic or saturated cyclic carboxylic acid salts where the carboxylateligand has preferably from 2 to 24 carbon atoms, such as acetate,propionate, butyrate, valerate, pivalate, caproate, isobuytlacetate,t-butyl-acetate, caprylate, heptanate, pelargonate, undecanoate, oleate,octoate, palmitate, myristate, margarate, stearate, arachate andtercosanoate. Non-limiting examples of the metal portion includes ametal from the Periodic Table of Elements selected from the group of Al,Mg, Ca, Sr, Sn, Ti, V, Ba, Zn, Cd, Hg, Mn, Fe, Co, Ni, Pd, Li and Na.

In one embodiment, the carboxylate metal salt is represented by thefollowing general formula:

M(Q)_(X)(OOCR)_(Y)

where M is a metal from Groups 1 to 16 and the Lanthanide and Actinideseries, preferably from Groups 1 to 7 and 13 to 16, more preferably fromGroups 3 to 7 and 13 to 16, even more preferably Groups 2 and 13, andmost preferably Group 13; Q is halogen, hydrogen, a hydroxy orhydroxide, alkyl, alkoxy, aryloxy, siloxy, silane sulfonate group orsiloxane; R is a hydrocarbyl radical having from 2 to 100 carbon atoms,preferably 4 to 50 carbon atoms; and x is an integer from 0 to 3 and yis an integer from 1 to 4 and the sum of x and y is equal to the valenceof the metal. In a preferred embodiment of the above formula y is aninteger from 1 to 3, preferably 1 to 2, especially where M is a Group 13metal.

Non-limiting examples of R in the above formula include hydrocarbylradicals having 2 to 100 carbon atoms that include alkyl, aryl,aromatic, aliphatic, cyclic, saturated or unsaturated hydrocarbylradicals. In an embodiment of the invention, R is a hydrocarbyl radicalhaving greater than or equal to 8 carbon atoms, preferably greater thanor equal to 12 carbon atoms and more preferably greater than or equal to17 carbon atoms. In another embodiment R is a hydrocarbyl radical havingfrom 17 to 90 carbon atoms, preferably 17 to 72, and most preferablyfrom 17 to 54 carbon atoms.

Non-limiting examples of Q in the above formula include one or more,same or different, hydrocarbon containing group such as alkyl,cycloalkyl, aryl, alkenyl, arylalkyl, arylalkenyl or alkylaryl,alkylsilane, arylsilane, alkylamine, arylamine, alkyl phosphide, alkoxyhaving from 1 to 30 carbon atoms. The hydrocarbon containing group maybe linear, branched, or even substituted. Also, Q in one embodiment isan inorganic group such as a halide, sulfate or phosphate.

In one embodiment, the more preferred carboxylate metal salts are thosealuminum carboxylates such as aluminum mono, di- and tri-stearates,aluminum octoates, oleates and cyclohexylbutyrates. In yet a morepreferred embodiment, the carboxylate metal salt is (CH₃(CH₂)₁₆COO)₃Al,a aluminum tri-stearate (preferred melting point 115° C.),(CH₃(CH₂)₁₆COO)₂—Al—OH, a aluminum di-stearate (preferred melting point145° C.), and a CH₃(CH₂)₁₆COO—Al(OH)₂, an aluminum mono-stearate(preferred melting point 155° C.).

Non-limiting commercially available carboxylate metal salts for exampleinclude Witco Aluminum Stearate # 18, Witco Aluminum Stearate # 22,Witco Aluminum Stearate # 132 and Witco Aluminum Stearate EA Food Grade,all of which are available from Witco Corporation, Memphis, Tenn.

In one embodiment the carboxylate metal salt has a melting point fromabout 30° C. to about 250° C., more preferably from about 37° C. toabout 220° C., even more preferably from about 50° C. to about 200° C.,and most preferably from about 100° C. to about 200° C. In a mostpreferred embodiment, the carboxylate metal salt is an aluminum stearatehaving a melting point in the range of from about 135° C. to about 165°C.

In another preferred embodiment the carboxylate metal salt has a meltingpoint greater than the polymerization temperature in the reactor.

Other examples of carboxylate metal salts include titanium stearates,tin stearates, calcium stearates, zinc stearates, boron stearate andstrontium stearates.

The carboxylate metal salt in one embodiment may be combined withantistatic agents such as fatty amines, for example, Kemamine AS 990/2zinc additive, a blend of ethoxylated stearyl amine and zinc stearate,or Kemamine AS 990/3, a blend of ethoxylated stearyl amine, zincstearate and octadecyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate. Boththese blends are available from Witco Corporation, Memphis, Tenn.

Method of Preparing the Catalyst Composition

The method for making the catalyst composition generally involves thecombining, contacting, blending, and/or mixing of a catalyst system orpolymerization catalyst with a carboxylate metal salt.

In one embodiment of the method of the invention, a conventional-typetransition metal catalyst and/or a bulky ligand metallocene-typecatalyst is combined, contacted, blended, and/or mixed with at least onecarboxylate metal salt. In a most preferred embodiment, theconventional-type transition metal catalyst and/or the bulky ligandmetallocene-type catalyst are supported on a carrier.

In another embodiment, the steps of the method of the invention includeforming a polymerization catalyst, preferably forming a supportedpolymerization catalyst, and contacting the polymerization catalyst withat least one carboxylate metal salt. In a preferred method, thepolymerization catalyst comprises a catalyst compound, an activator orcocatalyst and a carrier, preferably the polymerization catalyst is asupported bulky ligand metallocene-type catalyst.

One in the art recognizes that depending on the catalyst system and thecarboxylate metal salt used certain conditions of temperature andpressure would be required to prevent, for example, a loss in theactivity of the catalyst system.

In one embodiment of the method of the invention the carboxylate metalsalt is contacted with the catalyst system, preferably a supportedcatalyst system, most preferably a supported bulky ligandmetallocene-type catalyst system under ambient temperatures andpressures. Preferably the contact temperature for combining thepolymerization catalyst and the carboxylate metal salt is in the rangeof from 0° C. to about 100° C., more preferably from 15° C. to about 75°C., most preferably at about ambient temperature and pressure.

In a preferred embodiment, the contacting of the polymerization catalystand the carboxylate metal salt is performed under an inert gaseousatmosphere, such as nitrogen. However, it is contemplated that thecombination of the polymerization catalyst and the carboxylate metalsalt may be performed in the presence of olefin(s), solvents, hydrogenand the like.

In one embodiment, the carboxylate metal salt may be added at any stageduring the preparation of the polymerization catalyst.

In one embodiment of the method of the invention, the polymerizationcatalyst and the carboxylate metal salt are combined in the presence ofa liquid, for example the liquid may be a mineral oil, toluene, hexane,isobutane or a mixture thereof. In a more preferred method thecarboxylate metal salt is combined with a polymerization catalyst thathas been formed in a liquid, preferably in a slurry, or combined with asubstantially dry or dried, polymerization catalyst that has been placedin a liquid and reslurried.

In an embodiment, the contact time for the carboxylate metal salt andthe polymerization catalyst may vary depending on one or more of theconditions, temperature and pressure, the type of mixing apparatus, thequantities of the components to be combined, and even the mechanism forintroducing the polymerization catalyst/carboxylate metal saltcombination into the reactor.

Preferably, the polymerization catalyst, preferably a bulky ligandmetallocene-type catalyst compound and a carrier, is contacted with acarboxylate metal salt for a period of time from about a second to about24 hours, preferably from about 1 minute to about 12 hours, morepreferably from about 10 minutes to about 10 hours, and most preferablyfrom about 30 minutes to about 8 hours.

In an embodiment, the ratio of the weight of the carboxylate metal saltto the weight of the transition metal of the catalyst compound is in therange of from about 0.01 to about 1000, preferably in the range of from1 to about 100, more preferably in the range of from about 2 to about50, and most preferably in the range of from 4 to about 20. In oneembodiment, the ratio of the weight of the carboxylate metal salt to theweight of the transition metal of the catalyst compound is in the rangeof from about 2 to about 20, more preferably in the range of from about2 to about 12, and most preferably in the range of from 4 to about 10.

In another embodiment of the method of the invention, the weight percentof the carboxylate metal salt based on the total weight of thepolymerization catalyst is in the range of from about 0.5 weight percentto about 500 weight percent, preferably in the range of from 1 weightpercent to about 25 weight percent, more preferably in the range of fromabout 2 weight percent to about 12 weight percent, and most preferablyin the range of from about 2 weight percent to about 10 weight percent.In another embodiment, the weight percent of the carboxylate metal saltbased on the total weight of the polymerization catalyst is in the rangeof from 1 to about 50 weight percent, preferably in the range of from 2weight percent to about 30 weight percent, and most preferably in therange of from about 2 weight percent to about 20 weight percent.

In one embodiment, where the process of the invention is producing apolymer product having a density greater than 0.910 g/cc, the totalweight percent of the carboxylate metal salt based on the total weightof the polymerization catalyst is greater than 1 weight percent. In yetanother embodiment, where the process of the invention is producing apolymer product having a density less than 0.910 g/cc, the total weightpercent of the carboxylate metal salt based on the total weight of thepolymerization catalyst is greater than 3 weight percent. If thepolymerization catalyst includes a carrier, the total weight of thepolymerization catalyst includes the weight of the carrier.

It is believed that the more metal of the activator, for example totalaluminum content or free aluminum content (the alkyl aluminum content inalumoxane), present in the polymerization catalyst, the more carboxylatemetal salt is required. Manipulating the amounts or loadings of thepolymerization catalyst components, i.e. the free aluminum may provide ameans for adjusting the level of carboxylate metal salt.

Mixing techniques and equipment contemplated for use in the method ofthe invention are well known. Mixing techniques may involve anymechanical mixing means, for example shaking, stirring, tumbling, androlling. Another technique contemplated involves the use offluidization, for example in a fluid bed reactor vessel where circulatedgases provide the mixing. Non-limiting examples of mixing equipment forcombining, in the most preferred embodiment a solid polymerizationcatalyst and a solid carboxylate metal salt, include a ribbon blender, astatic mixer, a double cone blender, a drum tumbler, a drum roller, adehydrator, a fluidized bed, a helical mixer and a conical screw mixer.

In an embodiment of the method of the invention, a supportedconventional-type transition metal catalyst, preferably a supportedbulky ligand metallocene-type catalyst, is tumbled with a carboxylatemetal salt for a period of time such that a substantial portion of thesupported catalyst is intimately mixed and/or substantially contactedwith the carboxylate metal salt.

In a preferred embodiment of the invention the catalyst system of theinvention is supported on a carrier, preferably the supported catalystsystem is substantially dried, preformed, substantially dry and/or freeflowing. In an especially preferred method of the invention, thepreformed supported catalyst system is contacted with at least onecarboxylate metal salt. The carboxylate metal salt may be in solution orslurry or in a dry state, preferably the carboxylate metal salt is in asubstantially dry or dried state. In the most preferred embodiment, thecarboxylate metal salt is contacted with a supported catalyst system,preferably a supported bulky ligand metallocene-type catalyst system ina rotary mixer under a nitrogen atmosphere, most preferably the mixer isa tumble mixer, or in a fluidized bed mixing process, in which thepolymerization catalyst and the carboxylate metal salt are in a solidstate, that is they are both substantially in a dry state or in a driedstate.

In an embodiment of the method of the invention a conventional-typetransition metal catalyst compound, preferably a bulky ligandmetallocene-type catalyst compound, is contacted with a carrier to forma supported catalyst compound. In this method, an activator or acocatalyst for the catalyst compound is contacted with a separatecarrier to form a supported activator or supported cocatalyst. It iscontemplated in this particular embodiment of the invention, that acarboxylate metal salt is then mixed with the supported catalystcompound or the supported activator or cocatalyst, in any order,separately mixed, simultaneously mixed, or mixed with only one of thesupported catalyst, or preferably the supported activator prior tomixing the separately supported catalyst and activator or cocatalyst.

As a result of using the combination of polymerizationcatalyst/carboxylate metal salt of the invention it may be necessary toimprove the overall catalyst flow into the reactor. Despite the factthat the catalyst flow is not as good as a catalyst without thecarboxylate metal salt, the flowability of the catalyst/carboxylatecombination of the invention was not a problem. If catalyst flow needsimprovement, it is well known in the art to use bin vibrators, orcatalyst feeder brushes and feeder pressure purges and the like.

In another embodiment, the polymerization catalyst/carboxylate metalsalt may be contacted with a liquid, such as mineral oil and introducedto a polymerization process in a slurry state. In this particularembodiment, it is preferred that the polymerization catalyst is asupported polymerization catalyst.

In some polymerization processes smaller particle size support materialsare preferred. However, the operability of these processes is morechallenging. It has been discovered that utilizing the polymerizationcatalyst and carboxylate metal salt combination of the invention,smaller particle size support materials may be used successfully. Forexample, silica having an average particle size from about 10 microns to80 microns. Silica materials of this size are available from CrosfieldLimited, Warrington, England, for example Crosfield ES-70 having anaverage particle size of 35 to 40 microns. Not wishing to bound by anytheory, it is traditionally believed that using smaller average particlesize supports produces more fines and results in a more sheeting pronesupported catalyst. It is also believed that the use of a carboxylatemetal salt with the polymerization catalyst provides for better particlegrowth during polymerization. This better particle morphology isbelieved to result in fewer fines and a reduced tendency for sheeting tooccur. Thus, the use of a carboxylate metal salt allows for the use of asmaller support material.

In an embodiment, the method of the invention provides for co-injectingan unsupported polymerization catalyst and a carboxylate metal salt intothe reactor. In one embodiment the polymerization catalyst is used in anunsupported form, preferably in a liquid form such as described in U.S.Pat. Nos. 5,317,036 and 5,693,727 and European publication EP-A-0 593083, all of which are herein incorporated by reference. Thepolymerization catalyst in liquid form can be fed with a carboxylatemetal salt to a reactor using the injection methods described in PCTpublication WO 97/46599, which is fully incorporated herein byreference.

Where a carboxylate metal salt and an unsupported bulky ligandmetallocene-type catalyst system combination is utilized, the mole ratioof the metal of the activator component to the metal of the bulky ligandmetallocene-type catalyst compound is in the range of between 0.3:1 to10,000:1, preferably 100:1 to 5000:1, and most preferably 500:1 to2000:1.

Polymerization Process

The catalysts and catalyst systems of the invention described above aresuitable for use in any polymerization process. Polymerization processesinclude solution, gas phase, slurry phase and a high pressure process ora combination thereof. Particularly preferred is a gas phase or slurryphase polymerization of one or more olefins at least one of which isethylene or propylene.

In one embodiment, the process of this invention is directed toward asolution, slurry or gas phase polymerization process of one or moreolefin monomers having from 2 to 30 carbon atoms, preferably 2 to 12carbon atoms, and more preferably 2 to 8 carbon atoms. The invention isparticularly well suited to the polymerization of two or more olefinmonomers of ethylene, propylene, butene-1, pentene-1,4-methyl-pentene-1,hexene-1, octene-1 and decene-1.

Other monomers useful in the process of the invention includeethylenically unsaturated monomers, diolefins having 4 to 18 carbonatoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers andcyclic olefins. Non-limiting monomers useful in the invention mayinclude norbornene, norbornadiene, isobutylene, vinylbenzocyclobutane,styrenes, alkyl substituted styrene, ethylidene norbornene, isoprene,dicyclopentadiene and cyclopentene.

In the most preferred embodiment of the process of the invention, acopolymer of ethylene is produced, where with ethylene, a comonomerhaving at least one alpha-olefin having from 4 to 15 carbon atoms,preferably from 4 to 12 carbon atoms, and most preferably from 4 to 8carbon atoms, is polymerized in a gas phase process.

In another embodiment of the process of the invention, ethylene orpropylene is polymerized with at least two different comonomers,optionally one of which may be a diene, to form a terpolymer.

In one embodiment, the invention is directed to a process, particularlya gas phase or slurry phase process, for polymerizing propylene alone orwith one or more other monomers including ethylene, and olefins havingfrom 4 to 12 carbon atoms. Polypropylene polymers may be produced usingparticularly bridged bulky ligand metallocene-type catalysts asdescribed in U.S. Pat. Nos. 5,296,434 and 5,278,264, both of which areherein incorporated by reference.

Typically in a gas phase polymerization process a continuous cycle isemployed where in one part of the cycle of a reactor system, a cyclinggas stream, otherwise known as a recycle stream or fluidizing medium, isheated in the reactor by the heat of polymerization. This heat isremoved from the recycle composition in another part of the cycle by acooling system external to the reactor. Generally, in a gas fluidizedbed process for producing polymers, a gaseous stream containing one ormore monomers is continuously cycled through a fluidized bed in thepresence of a catalyst under reactive conditions. The gaseous stream iswithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product is withdrawn from the reactor and freshmonomer is added to replace the polymerized monomer. (See for exampleU.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749,5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228 allof which are fully incorporated herein by reference.)

The reactor pressure in a gas phase process may vary from about 100 psig(690 kPa) to about 500 psig (3448 kPa), preferably in the range of fromabout 200 psig (1379 kPa) to about 400 psig (2759 kPa), more preferablyin the range of from about 250 psig (1724 kPa) to about 350 psig (2414kPa).

The reactor temperature in the gas phase process may vary from about 30°C. to about 120° C., preferably from about 60° C. to about 115° C., morepreferably in the range of from about 70° C. to 110° C., and mostpreferably in the range of from about 70° C. to about 95° C.

Other gas phase processes contemplated by the process of the inventioninclude those described in U.S. Pat. Nos. 5,627,242, 5,665,818 and5,677,375, and European publications EP-A-0 794 200, EP-A-0 802 202 andEP-B-634 421 all of which are herein fully incorporated by reference.

In a preferred embodiment, the reactor utilized in the present inventionis capable and the process of the invention is producing greater than500 lbs of polymer per hour (227 Kg/hr) to about 200,000 lbs/hr (90,900Kg/hr) or higher of polymer, preferably greater than 1000 lbs/hr (455Kg/hr), more preferably greater than 10,000 lbs/hr (4540 Kg/hr), evenmore preferably greater than 25,000 lbs/hr (11,300 Kg/hr), still morepreferably greater than 35,000 lbs/hr (15,900 Kg/hr), still even morepreferably greater than 50,000 lbs/hr (22,700 Kg/hr) and most preferablygreater than 65,000 lbs/hr (29,000 Kg/hr) to greater than 100,000 lbs/hr(45,500 Kg/hr).

A slurry polymerization process generally uses pressures in the range offrom about 1 to about 50 atmospheres and even greater and temperaturesin the range of 0° C. to about 120° C. In a slurry polymerization, asuspension of solid, particulate polymer is formed in a liquidpolymerization diluent medium to which ethylene and comonomers and oftenhydrogen along with catalyst are added. The suspension including diluentis intermittently or continuously removed from the reactor where thevolatile components are separated from the polymer and recycled,optionally after a distillation, to the reactor. The liquid diluentemployed in the polymerization medium is typically an alkane having from3 to 7 carbon atoms. The medium employed should be liquid under theconditions of polymerization and relatively inert. When a propane mediumis used the process must be operated above the reaction diluent criticaltemperature and pressure. Preferably, a hexane or an isobutane medium isemployed.

A preferred polymerization technique of the invention is referred to asa particle form polymerization, or a slurry process where thetemperature is kept below the temperature at which the polymer goes intosolution. Such technique is well known in the art, and described in forinstance U.S. Pat. No. 3,248,179 which is fully incorporated herein byreference. Other slurry processes include those employing a loop reactorand those utilizing a plurality of stirred reactors in series, parallel,or combinations thereof. Non-limiting examples of slurry processesinclude continuous loop or stirred tank processes. Also, other examplesof slurry processes are described in U.S. Pat. No. 4,613,484, which isherein fully incorporated by reference.

In an embodiment the reactor used in the slurry process of the inventionis capable of and the process of the invention is producing greater than2000 lbs of polymer per hour (907 Kg/hr), more preferably greater than5000 lbs/hr (2268 Kg/hr), and most preferably greater than 10,000 lbs/hr(4540 Kg/hr). In another embodiment the slurry reactor used in theprocess of the invention is producing greater than 15,000 lbs of polymerper hour (6804 Kg/hr), preferably greater than 25,000 lbs/hr (11,340Kg/hr) to about 100,000 lbs/hr (45,500 Kg/hr).

Examples of solution processes are described in U.S. Pat. Nos. 4,271,060and 5,589,555, which are fully incorporated herein by reference

A preferred process of the invention is where the process, preferably aslurry or gas phase process is operated in the presence of a bulkyligand metallocene-type catalyst system and in the absence of oressentially free of any scavengers, such as triethylaluminum,trimethylaluminum, tri-isobutylaluminum and tri-n-hexylaluminum anddiethyl aluminum chloride, dibutyl zinc and the like. This preferredprocess is described in PCT publication WO 96/08520 and U.S. Pat. Nos.5,712,352 and 5,763,543 which are herein fully incorporated byreference. However, it has been discovered that a polymerization processutilizing the catalyst system/carboxylate metal salt combination of theinvention may be operated with a small amount of scavenger with reducedor no effect on process operability and catalyst performance. Thus, inone embodiment, the invention provides a process for polymerizingolefin(s) in a reactor in the presence of a bulky ligandmetallocene-type catalyst system, a carboxylate metal salt and ascavenger.

In one embodiment, the polymerization catalyst and/or catalystcomposition, the polymerization catalyst and the carboxylate metal salthave a productivity greater than 1500 grams of polymer per gram ofcatalyst, preferably greater than 2000 grams of polymer per gram ofcatalyst, more preferably greater than 2500 grams of polymer per gram ofcatalyst and most preferably greater than 3000 grams of polymer per gramof catalyst.

In another embodiment, the polymerization catalyst and/or catalystcomposition, the polymerization catalyst and the carboxylate metal salt,have a productivity greater than 2000 grams of polymer per gram ofcatalyst, preferably greater than 3000 grams of polymer per gram ofcatalyst, more preferably greater than 4000 grams of polymer per gram ofcatalyst and most preferably greater than 5000 grams of polymer per gramof catalyst.

In one embodiment, the polymerization catalyst and/or the catalystcomposition has a reactivity ratio generally less than 2, more typicallyless than 1. Reactivity ratio is defined to be the mole ratio ofcomonomer to monomer entering the reactor, for example as measured inthe gas composition in a gas phase process, divided by the mole ratio ofthe comonomer to monomer in the polymer product being produced. In apreferred embodiment, the reactivity ratio is less than 0.6, morepreferably less than 0.4, and most preferably less than 0.3. In the mostpreferred embodiment, the monomer is ethylene and the comonomer is anolefin having 3 or more carbon atoms, more preferably an alpha-olefinhaving 4 or more carbon atoms, and most preferably an alpha-olefinselected from the group consisting of butene-1,4-methyl-pentene-1,pentene-1, hexene-1 and octene-1.

In another embodiment of the invention, when transitioning from a firstpolymerization catalyst to a second polymerization catalyst, preferablywhere the first and second polymerization catalysts are bulky ligandmetallocene-type catalyst compound, more preferably where the secondpolymerization catalyst is a bridged, bulky ligand metallocene-typecatalyst compound, it would be preferable during the transition to use acatalyst composition of a carboxylate metal salt combined with abridged, bulky ligand metallocene-type catalyst.

When starting up a polymerization process, especially a gas phaseprocess, there is a higher tendency for operability problems to occur.Thus, it is contemplated in the present invention that a polymerizationcatalyst and carboxylate metal salt mixture is used on start-up toreduce or eliminate start-up problems. Furthermore, it also contemplatedthat once the reactor is operating in a stable state, a transition tothe same or a different polymerization catalyst without the carboxylatemetal salt can be made.

In another embodiment, during a polymerization process that is or isabout to be disrupted, a polymerization catalyst/carboxylate metal saltmixture of the invention could be transitioned to. This switching ofpolymerization catalysts is contemplated to occur when operabilityproblems arise. Indications of operability problems are well known inthe art. Some of which in a gas phase process include temperatureexcursions in the reactor, unexpected pressure changes, excessive staticgeneration or unusually high static spikes, chunking, sheeting and thelike. In an embodiment, the carboxylate metal salt may be added directlyto the reactor, particularly when operability problems arise.

It has also been discovered that using the polymerization catalystcombined with a carboxylate metal salt of the invention it is easier toproduce fractional melt index and higher density polymers. In oneembodiment, the invention provides for a process for polymerizingolefin(s) in a reactor in the presence of a polymerization catalyst incombination with a carboxylate metal salt to produce a polymer producthaving a melt index less than about 1 dg/min and a density greater than0.920 g/cc, more preferably the polymer product has a melt index lessthan about 0.75 dg/min and a density greater than 0.925 g/cc. Preferablythe polymerization catalyst is a bulky ligand metallocene-type catalyst,more preferably the process is a gas phase process and thepolymerization catalyst includes a carrier.

It is contemplated that using the combination polymerizationcatalyst/carboxylate metal salt of the invention, transitioning to oneof the more difficult grades of polymers would be simpler. Thus, in oneembodiment, the invention is directed to a process for polymerizingolefin(s) in the presence of a first catalyst composition, under steadystate conditions, preferably gas phase process conditions, to produce afirst polymer product. The first polymer product having a densitygreater than 0.87 g/cc, preferably greater than 0.900 g/cc, morepreferably greater than 0.910 g/cc, and a melt index in the range offrom 1 dg/min to about 200 dg/min, preferably in the range of greaterthan 1 dg/min to about 100 dg/min, more preferably from greater than 1dg/min to about 50 dg/min, most preferably from greater than 1 dg/min toabout 20 dg/min. This process further comprises the step oftransitioning to a second catalyst composition to produce second polymerproduct having a density greater than 0.920 g/cc, preferably greaterthan 0.925 g/cc, and a melt index less than 1 dg/min, preferably lessthan 0.75 dg/min. The second catalyst composition comprising, incombination, a conventional-type transition metal catalyst and/or abulky ligand metallocene-type catalyst, and a carboxylate metal salt. Itis also within the scope of this particular embodiment to transitionfrom a first polymer product having an I₂₁/I₂ (described below) of lessthan 25 to a second polymer product having an I₂₁/I₂ greater than 25,preferably greater than 30, and even more preferably greater than 35.

In yet another embodiment, the process of the invention involvesalternating between a first catalyst composition comprising a firstpolymerization catalyst/carboxylate metal salt mixture and a catalystcomposition of a second polymerization catalyst without a carboxylatemetal salt to improve the overall process operability. In a furtherembodiment, the first and second catalyst compositions described abovecan be used simultaneously, for example as a mixture or injected into areactor separately. In any of these embodiment, the first and secondpolymerization catalysts may be the same or different.

Polymer Product of the Invention

The polymers produced by the process of the invention can be used in awide variety of products and end-use applications. The polymers producedby the process of the invention include linear low density polyethylene,elastomers, plastomers, high density polyethylenes, low densitypolyethylenes, polypropylene and polypropylene copolymers.

The polymers, typically ethylene based polymers, have a density in therange of from 0.86 g/cc to 0.97 g/cc, preferably in the range of from0.88 g/cc to 0.965 g/cc, more preferably in the range of from 0.900 g/ccto 0.96 g/cc, even more preferably in the range of from 0.905 g/cc to0.95 g/cc, yet even more preferably in the range from 0.910 g/cc to0.940 g/cc, and most preferably greater than 0.915 g/cc, preferablygreater than 0.920 g/cc, and most preferably greater than 0.925 g/cc.

The polymers produced by the process of the invention typically have amolecular weight distribution, a weight average molecular weight tonumber average molecular weight (M_(w)/M_(n)) of greater than 1.5 toabout 15, particularly greater than 2 to about 10, more preferablygreater than about 2.2 to less than about 8, and most preferably from2.5 to 8. The ratio of M_(w)/M_(n) can be measured by gel permeationchromatography techniques well known in the art.

Also, the polymers of the invention typically have a narrow compositiondistribution as measured by Composition Distribution Breadth Index(CDBI). Further details of determining the CDBI of a copolymer are knownto those skilled in the art. See, for example, PCT Patent Application WO93/03093, published Feb. 18, 1993 which is fully incorporated herein byreference.

The bulky ligand metallocene-type catalyzed polymers of the invention inone embodiment have CDBI's generally in the range of greater than 50% to99%, preferably in the range of 55% to 85%, and more preferably 60% to80%, even more preferably greater than 60%, still even more preferablygreater than 65%.

In another embodiment, polymers produced using a conventional-typetransition metal catalyst have a CDBI less than 50%, more preferablyless than 40%, and most preferably less than 30%.

The polymers of the present invention in one embodiment have a meltindex (MI) or (I₂) as measured by ASTM-D-1238-E in the range from 0.01dg/min to 1000 dg/min, more preferably from about 0.01 dg/min to about100 dg/min, even more preferably from about 0.1 dg/min to about 50dg/min, and most preferably from about 0.1 dg/min to about 10 dg/min.

The polymers of the invention in one embodiment have a melt index ratio(I₂₁/I₂) (I₂₁ is measured by ASTM-D-1238-F) of from 10 to less than 25,more preferably from about 15 to less than 25.

The polymers of the invention in a preferred embodiment have a meltindex ratio (I₂₁/I₂) (I₂₁ is measured by ASTM-D-1238-F) of frompreferably greater than 25, more preferably greater than 30, even morepreferably greater that 40, still even more preferably greater than 50and most preferably greater than 65.

In yet another embodiment, propylene based polymers are produced in theprocess of the invention. These polymers include atactic polypropylene,isotactic polypropylene, and syndiotactic polypropylene. Other propylenepolymers include propylene random, block or impact copolymers.

Polymers produced by the process of the invention are useful in suchforming operations as film, sheet, and fiber extrusion and co-extrusionas well as blow molding, injection molding and rotary molding. Filmsinclude blown or cast films formed by coextrusion or by laminationuseful as shrink film, cling film, stretch film, sealing films, orientedfilms, snack packaging, heavy duty bags, grocery sacks, baked and frozenfood packaging, medical packaging, industrial liners, membranes, etc. infood-contact and non-food contact applications. Fibers include meltspinning, solution spinning and melt blown fiber operations for use inwoven or non-woven form to make filters, diaper fabrics, medicalgarments, geotextiles, etc. Extruded articles include medical tubing,wire and cable coatings, geomembranes, and pond liners. Molded articlesinclude single and multi-layered constructions in the form of bottles,tanks, large hollow articles, rigid food containers and toys, etc.

EXAMPLES

In order to provide a better understanding of the present inventionincluding representative advantages thereof, the following examples areoffered.

The properties of the polymer were determined by the following testmethods:

Density is measured in accordance with ASTM-D-1238.

The Fouling Index in the Tables below illustrates operability of thecatalyst. The higher the value the greater the fouling observed. AFouling Index of zero means substantially no or no visible fouling. AFouling Index of 1 is indicative of light fouling, where a very lightpartial coating of polymer on the stirrer blades of a 2 liter slurryisobutane polymerization reactor and/or no reactor body sheeting. AFouling Index of 2 is indicative of more than light fouling, where thestirrer blades have a heavier, painted-like, coating of polymer and/orthe reactor body wall has some sheeting in a band of 1 to 2 inches (2.54to 5.08 cm) wide on the reactor wall. A Fouling Index of 3 is consideredmedium fouling, where the stirrer blade has a thicker, latex-like,coating of polymer on the stirrer blade, some soft chunks in thereactor, and/or some reactor body sheeting with a band of 2 to 3 inch(5.08 to 7.62 cm) wide on the reactor wall. A Fouling Index of 4 isevidence of more than medium fouling, where the stirrer has a thick,latex-like, coating, some harder chunks/balls of polymer, and/or thereactor body wall sheeting band is from 3 to 4 inches (7.62 to 10.2 cm)wide.

Activity in the Tables below is measured in grams of polyethylene(PE)per gram of polymerization catalyst-hour (gPE/gCat.h).

Comparative Example 1 Preparation of Catalyst A

The bridged, bulky ligand metallocene-type catalyst compound used inthis Comparative Example 1 is adimethylsilyl-bis(tetrahydroindenyl)zirconium dichloride(Me₂Si(H₄Ind)₂ZrCl₂) available from Albemarle Corporation, Baton Rouge,La. The (Me₂Si(H₄Ind)₂ZrCl₂) catalyst compound was supported onCrosfield ES-70 grade silica dehydrated at 600° C. having approximately1.0 weight percent water Loss on Ignition (LOI). LOI is measured bydetermining the weight loss of the support material which has beenheated and held at a temperature of about 1000° C. for about 22 hours.The Crosfield ES-70 grade silica has an average particle size of 40microns and is available from Crosfield Limited, Warrington, England.

The first step in the manufacture of the supported bulky ligandmetallocene-type catalyst above involves forming a precursor solution.460 lbs (209 kg) of sparged and dried toluene is added to an agitatedreactor after which 1060 lbs (482 kg) of a 30 weight percentmethylaluminoxane (MAO) in toluene (available from Albemarle, BatonRouge, La.) is added. 947 lbs (430 kg) of a 2 weight percent toluenesolution of a dimethylsilyl-bis(tetrahydroindenyl) zirconium dichloridecatalyst compound and 600 lbs (272 kg) of additional toluene areintroduced into the reactor. The precursor solution is then stirred at80° F. to 100° F. (26.7° C. to 37.8° C.) for one hour.

While stirring the above precursor solution, 850 lbs (386 kg) of 600° C.Crosfield dehydrated silica carrier is added slowly to the precursorsolution and the mixture agitated for 30 min. at 80° F. to 100° F. (26.7to 37.8° C.). At the end of the 30 min. agitation of the mixture, 240lbs (109 kg) of a 10 weight percent toluene solution of AS-990(N,N-bis(2-hydroxylethyl) octadecylamine ((C₁₈H₃₇N(CH₂CH₂OH)₂) availableas Kemamine AS-990 from Witco Corporation, Memphis, Tenn., is addedtogether with an additional 110 lbs (50 kg) of a toluene rinse and thereactor contents then is mixed for 30 min. while heating to 175° F. (79°C.). After 30 min. vacuum is applied and the polymerization catalystmixture dried at 175° F. (79° C.) for about 15 hours to a free flowingpowder. The final polymerization catalyst weight was 1200 lbs (544 kg)and had a Zr wt % of 0.35 and an Al wt % of 12.0.

Example 1 Preparation of Catalyst B

A 1 kg sample of the polymerization catalyst prepared as described inComparative Example 1, Catalyst A, was weighed into a 3-liter glassflask under an inert atmosphere. 40 g of Witco Aluminum Stearate #22(AlSt #22) (CH₃(CH₂)₁₆COO)₂Al—OH available from Witco Corporation,Memphis, Tenn., was dried under vacuum at 85° C. and was added to theflask and the contents tumbled/mixed for 20 minutes at room temperature.The aluminum stearate appeared to be homogeneously dispersed throughoutthe catalyst particles.

Example 2 Preparation of Catalyst C

A 1 kg sample of the polymerization catalyst prepared as described inComparative Example 1, Catalyst A, was weighed into a 3-liter glassflask under an inert atmosphere. 20 g of Witco Aluminum Stearate #22(AlSt #22) (CH₃(CH₂)₁₆COO)₂Al—OH available from Witco Corporation,Memphis, Tenn., was dried under vacuum at 85° C. and was added to theflask and the contents tumbled/mixed for 20 minutes at room temperature.The aluminum stearate appeared to be homogeneously dispersed throughoutthe catalyst particles.

Example 3 Preparation of Catalyst D

A 1 kg sample of the polymerization catalyst prepared as described inComparative Example 1, Catalyst A, was weighed into a 3-liter glassflask under an inert atmosphere. 10 g of Witco Aluminum Stearate #22(AlSt #22) (CH₃(CH₂)₁₆COO)₂Al—OH available from Witco Corporation,Memphis, Tenn., was dried under vacuum at 85° C. and was added to theflask and the contents tumbled/mixed for 20 minutes at room temperature.The aluminum stearate appeared to be homogeneously dispersed throughoutthe catalyst particles.

Polymerization Process Using Catalyst A through D

A 2 liter autoclave reactor under a nitrogen purge was charged with 0.16mmoles triethylaluminum (TEAL), followed by 20 cc of hexene-1 comonomerand 800 cc of isobutane diluent. The contents of the reactor were heatedto 80° C., after which, 100 mg of each of the supported polymerizationcatalysts above, Catalyst A, B, C and D, were each separatelypolymerized as follows: Each polymerization catalyst was introducedconcurrently with ethylene into the reactor to make up a total reactorpressure of 325 psig (2240 kPa). The reactor temperature was maintainedat 85° C. and the polymerization was allowed to proceed for 40 min.After 40 minutes the reactor was cooled, ethylene was vented off and thepolymer dried and weighed to obtain the polymer yield. Table 1 belowprovides the yield activity data, as well as the fouling characteristicsobserved using Catalyst A with no aluminum stearate and Catalyst Bthrough D, each with various levels of aluminum stearate.

TABLE 1 AlSt Activity Fouling Example Catalyst Amount (g) (gPE/gCat · h)Index Comparative 1 A 0 1845 2.0 1 D 10 1680 1.5 2 C 20 1710 0 3 B 401650 0

Table 1 illustrates the effect of various levels of aluminum stearate oncatalyst activity and operability.

Comparative Example 2 Preparation of Catalyst E

Into a 2 gallon (7.57 liters) reactor was charged first with 2.0 litersof toluene then, 1060 g of 30 wt % methylalumoxane solution in toluene(available from Albemarle, Baton Rouge, La.), followed by 23.1 g ofbis(1,3-methyl-n-butyl cyclopentadienyl)zirconium dichloride as a 10%solution in toluene. The mixture was stirred for 60 minutes at roomtemperature after which 850 g of silica (Davison 948 dehydrated at 600°C. available from W. R. Grace, Davison Chemical Division, Baltimore,Md.) was added to the liquid with slow agitation. Stirring speed wasincreased for approximately 10 minutes to insure dispersion of thesilica into the liquid and then appropriate amount of toluene was addedto make up a slurry of liquid to solid having a consistency of 4 cc/g ofsilica. Mixing was continued for 15 minutes at 120 rpm after which 6 gof Kemamine AS-990 (available Witco Corporation, Memphis, Tenn.) wasdissolved in 100 cc of toluene and was added and stirred for 15 minutes.Drying was then initiated by vacuum and some nitrogen purge at 175° F.(79.4° C.). When the polymerization catalyst comprising the carrier,silica, appeared to be free flowing, it was cooled down and dischargedinto a nitrogen purged vessel. An approximate yield of 1 Kg of drypolymerization catalyst was obtained due to some loses due to drying.

Example 4 Preparation of Catalyst F

A sample of the polymerization catalyst prepared as described inComparative Example 2, Catalyst E, was dry blended with an amount ofWitco Aluminum Stearate #22 (AlSt #22) (available from WitcoCorporation, Memphis, Tenn.) equal to 2 weight percent based on thetotal weight of the supported polymerization catalyst. The AlSt #22 wasdried in a vacuum oven for 12 hours at 85° C. Under nitrogen, thepolymerization catalyst was then dry blended with the AlSt #22. Table 2illustrates the benefits of adding the carboxylate metal salt in theseexamples, aluminum stearate, to the polymerization catalyst. Theseexamples also show that the carboxylate metal salt has virtually noeffect on the molecular weight properties of the polymer formed.

The results of the polymerization runs for Catalysts E and F using thesame process as previously described above for Catalysts A through D areshown below in Table 2.

TABLE 2 Activity Amount (gPE/ Fouling MI MIR Example Catalyst AlSt gCat· h) Index (dg/min) (I₂₁/I₂) Comp. (2) E 0 1980 1.0 0.15 19.8 4 F 2 wt %1950 0 0.18 18.0

Comparative Example 3 Preparation of Catalyst G

Into a 2 gallon (7.57 liters) reactor was charged 1060 g of 30 wt %methylalumoxane (MAO), an activator, solution in toluene (PMAO, modifiedMAO available from Akzo Nobel, LaPorte, Tex.), followed by 1.5 liter oftoluene. While stirring 17.3 g ofbis(1,3-methyl-n-butylcyclopentadienyl)zirconium dichloride, a bulkyligand metallocene-type catalyst compound, as an 8 wt % solution intoluene was added to the reactor and the mixture was stirred for 60 minat room temperature to form a catalyst solution. The content of thereactor was unloaded to a flask and 850 g of silica dehydrated at 600°C. (available from Crosfield Limited, Warrington, England) was chargedto the reactor. The catalyst solution contained in the flask was thenadded slowly to the silica carrier in the reactor while agitatingslowly. More toluene (350 cc) was added to insure a slurry consistencyand the mixture was stirred for an additional 20 min. 6 g of KemamineAS-990 (available from Witco Corporation, Memphis, Tenn.) as a 10%solution in toluene was added and stirring continued for 30 min. at roomtemperature. The temperature was then raised to 68° C. (155° F.) andvacuum was applied in order to dry the polymerization catalyst. Dryingwas continued for approximately 6 hours at low agitation until thepolymerization catalyst appeared to be free flowing. It was thendischarged into a flask and stored under a N₂ atmosphere. The yield was1006 g due to some losses in the drying process. Analysis of thepolymerization catalyst was: Zr=0.30 wt %, Al=11.8 wt %.

Examples 5 and 6

In Examples 5 and 6, the polymerization catalyst prepared as describedin Comparative Example 3, Catalyst G, was coinjected with 4 weightpercent and 8 weight percent Witco Aluminum Stearate #22, (AlSt #22)(available from Witco Corporation, Memphis, Tenn.) based on the catalystcharge and injected into a polymerization reactor. The results of thepolymerization runs using Catalysts G, H and I in the same process aspreviously described for Catalysts A through D are shown in Table 3.

TABLE 3 Activity AlSt (gPE/ MI (I₂) MIR Fouling Example Catalyst (wt %)gCat · h) (dg/min) (I₂₁/I₂) Index Comp. (3) G 0 2535 0.13 21.4 4.0 5 H 42250 0.12 22.5 0 6 I 8 2010 0.12 22.5 0

Table 3 illustrates that even with a highly active, more fouling pronecatalyst, aluminum stearate is effective. It further illustrates thataluminum stearate does not materially change the productcharacteristics.

Examples 7 Though 11

Examples 7 and 8 use the same catalyst from Comparative Example 3,Catalyst G, with Calcium Stearate (CaSt) (Catalyst J) as the carboxylatemetal salt in Example 7 and Zinc Stearate (ZnSt) (Catalyst K) in Example8. The CaSt and ZnSt is available from Mallinkrodt Corporation,Phillipsbury, N.J. The polymerization process used for testing thecatalyst compositions of Examples 7 and 8 is the same as that describedand used above for Catalyst A through D.

Examples 9 through 11 use the same catalyst from Comparative Example 1,Catalyst A, with aluminum mono-stearate (Example 9, Catalyst L) as thecarboxylate metal salt, aluminum di-stearate (Example 10, Catalyst M)and aluminum tri-stearate (Example 11, Catalyst N). The polymerizationprocess later described herein and used in Examples 12 through 15 wasused to test the catalyst compositions of Examples 9 through 11,Catalysts L, M and N. Table 4 below provides these results.

TABLE 4 Amount of Activity Carboxylate Carboxylate (gPE/ Fouling ExampleCatalyst Metal Salt (wt %) gCat · h) Index Comp. (3) G None 0 2535 4.0 7J CaSt 2 2295 2.0 8 K ZnSt 4 2340 3.0 Comp. (1) A None 0 1845 2.0 9 L Almono- 5 NA 0 Stearate 10  M Al di-Stearate 5 NA 0 11  N Al tri-Stearate5 NA 0.5

Examples 7 and 8 illustrate the use of different carboxylate metalsalts. Specifically in Examples 7 and 8, the metal of the stearate, Caand Zn, are shown to be effective in reducing fouling. Examples 9, 10and 11 illustrate several types of carboxylate aluminum salts,specifically that different forms of aluminum stearate are effective.From the data in Table 4 it can be seen that mono-stearates anddi-stearates are most effective.

Examples 12 Through 15

In Examples 12 through 15 the dry blending method described in Example 1was used with Catalyst A of Comparative Example 1 with various types ofcarboxylate metal salts. The quantity and type of carboxylate metal saltis set out in Table 5. The following polymerization process describedbelow was used for each polymerization catalyst/carboxylate metal saltcombination, Catalysts O, P, Q and R.

Polymerization Process for Examples 12 Through 15

A 2 liter autoclave reactor under a nitrogen purge was charged with 0.16mmoles triethylaluminum (TEAL), followed by 25 cc of hexene-1 comonomerand 800 cc of isobutane diluent. The contents of the reactor were heatedto 80° C., after which, 100 mg of each of the supported polymerizationcatalysts/carboxylate metal salt mixture described above, (Catalyst Awith the specified amounts of carboxylate metal salt as reported inTable 5), were each separately polymerized as follows: Eachpolymerization catalyst/carboxylate metal salt combination wasintroduced concurrently with ethylene into the reactor to make up atotal reactor pressure of 325 psig (2240 kPa). The reactor temperaturewas maintained at 85° C. and the polymerization was allowed to proceedfor 40 min. After 40 minutes the reactor was cooled, ethylene was ventedoff and the polymer dried and weighed to obtain the polymer yield.

The results are given in Table 5 below. Of particular interest, theseExamples 12, 13, 14, and 15 illustrate a preference for having a bulkyR-group on the carboxylate metal salts, specifically, the aluminumcarboxylates.

TABLE 5 Carboxylate Amount of Fouling Example Catalyst Metal SaltCarboxylate (wt %) Index 12 O Al Acetate 5.0 4 13 P Al Octoate 5.0 3 14Q Al Naphthenate 5.0 2 15 R Al Oleate 5.0 0

Examples 16 through 18 and Comparative Example 4

Examples 16, 17 and 18 and Comparative Example 4 illustrate theeffectiveness of the use of a carboxylate metal salt, particularlyaluminum stearate, in a fluid bed gas phase process in combination witha bulky ligand metallocene-type catalyst system to produce grades ofpolymer that are typically more difficult to produce especially in termsof operability. Traditionally, fractional melt index higher densitygrades are difficult to make from a reactor operability standpoint. Thepolymerization catalyst used in the polymerizations of Examples 16, 17and 18 and Comparative Example 4 were run in the process described belowand the results of which are indicated in Table 6 below.

Polymerization Process

The Catalysts A, B and F described above were then separately tested ina continuous gas phase fluidized bed reactor which comprised a nominal18 inch, schedule 60 reactor having an internal diameter of 16.5 inches.(41.9 cm) The fluidized bed is made up of polymer granules. The gaseousfeed streams of ethylene and hydrogen together with liquid comonomerwere mixed together in a mixing tee arrangement and introduced below thereactor bed into the recycle gas line. Hexene-1 was used as thecomonomer. The individual flow rates of ethylene, hydrogen and comonomerwere controlled to maintain fixed composition targets. The ethyleneconcentration was controlled to maintain a constant ethylene partialpressure. The hydrogen was controlled to maintain constant hydrogen toethylene mole ratio. The concentration of all the gases were measured byan on-line gas chromatograph to ensure relatively constant compositionin the recycle gas stream. The solid supported bulky ligandmetallocene-type catalyst system listed in Table 6, was injecteddirectly into the fluidized bed using purified nitrogen at 1.5 lbs/hr(0.68 kg/hr). The reacting bed of growing polymer particles wasmaintained in a fluidized state by the continuous flow of the make upfeed and recycle gas through the reaction zone. A superficial gasvelocity of 1 to 3 ft/sec (30.5 cm/sec to 91.4 cm/sec) was used toachieve this. The reactor was operated at a total pressure of 300 psig(2069 kPa), a reactor temperature of 85° C. and a superficial gasvelocity of 2.25 ft/sec (68.6 cm/sec) was used to achieve fluidizationof the granules. To maintain a constant reactor temperature, thetemperature of the recycle gas is continuously adjusted up or down toaccommodate any changes in the rate of heat generation due to thepolymerization. The fluidized bed was maintained at a constant height bywithdrawing a portion of the bed at a rate equal to the rate offormation of particulate product. The product is removedsemi-continuously via a series of valves into a fixed volume chamber,which is simultaneously vented back to the reactor. This allows forhighly efficient removal of the product, while at the same timerecycling a large portion of the unreacted gases back to the reactor.This product is purged to remove entrained hydrocarbons and treated witha small stream of humidified nitrogen to deactivate any trace quantitiesof residual catalyst.

TABLE 6 EXAMPLE 16 17 18 Comp. 4 BTO's 9 10 8 3 Catalyst B F F A Cat.Activity¹ 4300 4000 3300 4800 MI (dg/min) 0.78 0.73 0.43 1.47 Density(g/cc) 0.9243 0.9248 0.9230 0.9188 Resin bulk 0.49 0.44 0.45 0.48density (g/cc) ¹Pounds of Polymer per Pound of polymerization catalyst.

By using carboxylate metal salts in combination with the polymerizationcatalysts, reactor operability improves tremendously. Table 6illustrates a gas phase reactor operating without any problems inproducing fractional melt index polymers for many bed turnovers (BTO).Specifically shown is that using a polymerization catalyst without thecarboxylate metal salt, as in Comparative Example 4 (without aluminumstearate), the reactor was shut down due to fouling and sheeting in lessthan 3 bed turnovers at around a melt index of 1.5 dg/min and a densityof 0.9188 g/cc. In an embodiment of the invention the process isoperating for a period greater than 4 bed turnovers, more preferablygreater than 5 bed turnovers and most preferably greater than 6 bedturnovers. A bed turnover is when the total weight of the polymerdischarged from the reactor is approximately equal or equal to the bedweight in the reactor.

It is known in the art that reducing resin bulk density can improveoperability of a polymerization process, particularly a gas phasefluidized bed polymerization process. Note from Table 6 that the resinbulky density did not change much, however, the operability of theprocess of the invention was surprisingly, substantially improved, whena carboxylate metal salt is combined with the polymerization catalyst.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For example, it is contemplated that acarboxylate metal salt can be added to reactor in addition to beingcontacted with the catalyst system of the invention. It is alsocontemplated that the process of the invention may be used in a seriesreactor polymerization process. For example, a supported bulky ligandmetallocene-type catalyst system free of a carboxylate metal salt isused in one reactor and a supported, bridged, bulky ligandmetallocene-type catalyst system having been contacted with acarboxylate metal salt being used in another or vice-versa. It is evenfurther contemplated that the components of a carboxylate metal salt, acarboxylic acid and metal compound, for example a metal hydroxycompound, may be added to the reactor or the polymerization catalyst toform in situ the reactor or with the catalyst. It is also contemplatedthat a carboxylate metal salt may be separately supported on a carrierdifferent from the polymerization catalyst, preferably a supportedpolymerization catalyst. For this reason, then, reference should be madesolely to the appended claims for purposes of determining the true scopeof the present invention.

1. A catalyst composition comprising, in combination, a polymerizationcatalyst and a carboxylate metal salt.
 2. The catalyst composition ofclaim 1 wherein the polymerization catalyst comprises aconventional-type transition metal catalyst compound.
 3. The catalystcomposition of claim 1 wherein the polymerization catalyst comprises abulky ligand metallocene-type catalyst compound.
 4. The catalystcomposition of a claim 1 wherein the carboxylate metal salt isrepresented by the formula:MQ_(X)(OOCR)_(y) where M is a metal from the Periodic Table of Elements;Q is halogen, or a hydroxy, alkyl, alkoxy, aryloxy, siloxy, silane orsulfonate group; R is a hydrocarbyl radical having from 2 to 100 carbonatoms; x is an integer from 0 to 3; y is an integer from 1 to 4; and thesum of x and y is equal to the valence of the metal M.
 5. The catalystcomposition of claim 4 wherein M is a metal from Groups 1 to 7 andGroups 13 to 16; Q is halogen or a hydroxy group; and R is a hydrocarbylradical having from 4 to 24 carbon atoms.
 6. The catalyst composition ofclaim 4 wherein y is either 1 or 2, M is a Group 2 or 13 metal, Q is ahydroxy group, and R is a hydrocarbyl radical having greater than 12carbon atoms.
 7. The catalyst composition of claim 1 wherein thecarboxylate metal salt is selected from the group consisting of aluminummono-stearate, aluminum di-stearate and aluminum tri-stearate or acombination thereof.
 8. The catalyst composition of claim 1 wherein thepolymerization catalyst comprises a carrier.